Dissipation generally leads to the decoherence of a quantum state. In contrast, numerous recent proposals have illustrated that dissipation can also be tailored to stabilize many-body entangled quantum states. While the focus of these works has been primarily on engineering the nonequilibrium steady state, we investigate the buildup of entanglement in the quantum trajectories. Specifically, we analyze the competition between two different dissipation channels arising from two incompatible continuous monitoring protocols. The first protocol locks the phase of neighboring sites upon registering a quantum jump, thereby generating a long-range entanglement through the system, while the second destroys the coherence via a dephasing mechanism. By studying the unraveling of stochastic quantum trajectories associated with the continuous monitoring protocols, we present a transition for the scaling of the averaged trajectory entanglement entropies, from critical scaling to area-law behavior. Our work provides an alternative perspective on the measurement-induced phase transition: the measurement can be viewed as monitoring and registering quantum jumps, offering an intriguing extension of these phase transitions through the long-established realm of quantum optics.

}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.126.123604}, author = {Van Regemortel, Mathias and Cian, Ze-Pei and Seif, Alireza and Dehghani, Hossein and Hafezi, Mohammad} } @article { WOS:000730855600005, title = {Estimating disorder and its adverse effects in semiconductor Majorana nanowires}, journal = {Phys. Rev. Mater.}, volume = {5}, number = {12}, year = {2021}, month = {DEC 9}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We use the available transport measurements in the literature to develop a dataset for the likely amount of disorder in semiconductor (InAs and InSb) materials which are used in fabricating the superconductor-semiconductor nanowire samples in the experimental search for Majorana zero modes. Using the estimated disorder in direct Majorana simulations, we conclude that the current level of disorder in semiconductor Majorana nanowires is at least an order of magnitude higher than that necessary for the emergence of topological Majorana zero modes. In agreement with existing results, we find that our estimated disorder leads to the occasional emergence of trivial zero modes, which can be post-selected and then further fine-tuned by varying system parameters (e.g., tunnel barrier), leading to trivial zero-bias conductance peaks in tunneling spectroscopy with similar to 2e(2)/h magnitude. Most calculated tunnel spectra in these disordered systems, however, manifest essentially no significant features, which is also consistent with the current experimental status, where zero-bias peaks are found only occasionally in some samples under careful fine-tuning.}, issn = {2475-9953}, doi = {10.1103/PhysRevMaterials.5.124602}, author = {Ahn, Seongjin and Pan, Haining and Woods, Benjamin and Stanescu, Tudor D. and Das Sarma, Sankar} } @article { WOS:000647487800006, title = {Exact analytical treatment of multiqubit noisy dynamics in exchange-coupled semiconductor spin qubits}, journal = {Phys. Rev. B}, volume = {103}, number = {20}, year = {2021}, month = {MAY 3}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Charge noise remains the primary obstacle to the development of quantum information technologies with semiconductor spin qubits. We use an exact analytical calculation to determine the effects of quasistatic charge noise on a ring of three equally spaced exchange-coupled quantum dots. We calculate the disorder-averaged return probability from a specific initial state and use it to determine the coherence time T-2{*} and show that it depends on only the disorder strength and not the mean interaction strength. We also use a perturbative approach to investigate other arrangements of three or four qubits, finding that the return probability contains multiple oscillation frequencies. These oscillations decay in a Gaussian manner, determined by differences in energy levels of the Hamiltonian. We give quantitative values for gate times resulting in several target fidelities. We find that the decoherence time decreases with an increasing number of qubits. Our work provides useful analytical insight into the charge noise dynamics of coupled spin qubits.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.103.205402}, author = {Buterakos, Donovan and Das Sarma, Sankar} } @article {zeuner_experimental_2021, title = {Experimental quantum homomorphic encryption}, journal = {npj Quantum Inform.}, volume = {7}, number = {1}, year = {2021}, note = {Place: HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY Publisher: NATURE RESEARCH Type: Article}, month = {feb}, abstract = {Quantum computers promise not only to outperform classical machines for certain important tasks, but also to preserve privacy of computation. For example, the blind quantum computing protocol enables secure delegated quantum computation, where a client can protect the privacy of their data and algorithms from a quantum server assigned to run the computation. However, this security comes with the practical limitation that the client and server must communicate after each step of computation. A practical alternative is homomorphic encryption, which does not require any interactions, while providing quantum-enhanced data security for a variety of computations. In this scenario, the server specifies the computation to be performed, and the client provides only the input data, thus enabling secure noninteractive computation. Here, we demonstrate homomorphic-encrypted quantum computing with unitary transformations of individual qubits, as well as multi-qubit quantum walk computations using single-photon states and non-birefringent integrated optics. The client encrypts their input in the photons{\textquoteright} polarization state, while the server performs the computation using the path degree of freedom. Our demonstration using integrated quantum photonics underlines the applicability of homomorphic-encrypted quantum computations, and shows the potential for delegated quantum computing using photons.}, doi = {10.1038/s41534-020-00340-8}, author = {Zeuner, Jonas and Pitsios, Ioannis and Tan, Si-Hui and Sharma, Aditya N. and Fitzsimons, Joseph F. and Osellame, Roberto and Walther, Philip} } @article { WOS:000648494200001, title = {Fast Logic with Slow Qubits: Microwave-Activated Controlled-Z Gate on Low-Frequency Fluxoniums}, journal = {Phys. Rev. X}, volume = {11}, number = {2}, year = {2021}, month = {MAY 3}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We demonstrate a controlled-Z gate between capacitively coupled fluxonium qubits with transition frequencies 72.3 and 136.3 MHz. The gate is activated by a 61.6-ns-long pulse at a frequency between noncomputational transitions vertical bar 10 > - vertical bar 20 > and vertical bar 11 > - vertical bar 21 >, during which the qubits complete only four and eight Larmor periods, respectively. The measured gate error of (8 +/- 1) x 10(-3) is limited by decoherence in the noncomputational subspace, which will likely improve in the next-generation devices. Although our qubits are about 50 times slower than transmons, the two-qubit gate is faster than microwave-activated gates on transmons, and the gate error is on par with the lowest reported. Architectural advantages of lowfrequency fluxoniums include long qubit coherence time, weak hybridization in the computational subspace, suppressed residual ZZ-coupling rate (here 46 kHz), and the absence of either excessive parameter-matching or complex pulse-shaping requirements.}, issn = {2160-3308}, doi = {10.1103/PhysRevX.11.021026}, author = {Ficheux, Quentin and Nguyen, Long B. and Somoroff, Aaron and Xiong, Haonan and Nesterov, Konstantin N. and Vavilov, Maxim G. and Manucharyan, Vladimir E.} } @article { WOS:000674692700001, title = {Faster Digital Quantum Simulation by Symmetry Protection}, journal = {PRX Quantum}, volume = {2}, number = {1}, year = {2021}, month = {FEB 12}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Simulating the dynamics of quantum systems is an important application of quantum computers and has seen a variety of implementations on current hardware. We show that by introducing quantum gates implementing unitary transformations generated by the symmetries of the system, one can induce destructive interference between the errors from different steps of the simulation, effectively giving faster quantum simulation by symmetry protection. We derive rigorous bounds on the error of a symmetry-protected simulation algorithm and identify conditions for optimal symmetry protection. In particular, when the symmetry transformations are chosen as powers of a unitary, the error of the algorithm is approximately projected to the so-called quantum Zeno subspaces. We prove a bound on this approximation error, exponentially improving a recent result of Burgarth, Facchi, Gramegna, and Pascazio. We apply the symmetry-protection technique to the simulations of the XXZ Heisenberg interactions with local disorder and the Schwinger model in quantum field theory. For both systems, the technique can reduce the simulation error by several orders of magnitude over the unprotected simulation. Finally, we provide numerical evidence suggesting that the technique can also protect simulation against other types of coherent, temporally correlated errors, such as the 1/f noise commonly found in solid-state experiments.}, doi = {10.1103/PRXQuantum.2.010323}, author = {Tran, Minh C. and Su, Yuan and Carney, Daniel and Taylor, Jacob M.} } @article { WOS:000712467500001, title = {Feedback-stabilized dynamical steady states in the Bose-Hubbard model}, journal = {Phys. Rev. Res.}, volume = {3}, number = {4}, year = {2021}, month = {OCT 27}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {The implementation of a combination of continuous weak measurement and classical feedback provides a powerful tool for controlling the evolution of quantum systems. In this paper, we investigate the potential of this approach from three perspectives. First, we consider a double-well system in the classical large-atom-number limit, deriving the exact equations of motion in the presence of feedback. Second, we consider the same system in the limit of small atom number, revealing the effect that quantum fluctuations have on the feedback scheme. Finally, we explore the behavior of modest-sized Hubbard chains using exact numerics, demonstrating the near-deterministic preparation of number states, a tradeoff between local and nonlocal feedback for state preparation, and evidence of a feedback-driven symmetry-breaking phase transition.}, doi = {10.1103/PhysRevResearch.3.043075}, author = {Young, Jeremy T. and Gorshkov, V, Alexey and Spielman, I. B.} } @article { WOS:000704419000003, title = {Fragile versus stable two-dimensional fermionic quasiparticles}, journal = {Phys. Rev. B}, volume = {104}, number = {12}, year = {2021}, month = {SEP 13}, publisher = {AMER PHYSICAL SOC}, type = {Editorial Material}, abstract = {We provide a comprehensive theoretical investigation of the Fermi liquid quasiparticle description in two-dimensional electron gas interacting via the long-range Coulomb interaction by calculating the electron self-energy within the leading-order approximation, which is exact in the high-density limit. We find that the quasiparticle energy is larger than the imaginary part of the self-energy up to very high energies, implying that the basic Landau quasiparticle picture is robust up to far above the Fermi energy. We find, however, that the quasiparticle picture becomes fragile in a small discrete region around a critical wave vector where the quasiparticle spectral function strongly deviates from the expected quasiparticle Lorentzian line shape with a vanishing renormalization factor. We show that such a non-Fermi liquid behavior arises due to the coupling of quasiparticles with the collective plasmon mode. This situation is somewhat intermediate between the one-dimensional interacting electron gas (i.e., Luttinger liquid), where the Landau Fermi liquid theory completely breaks down since only bosonic collective excitations exist, and three-dimensional electron gas, where quasiparticles are well-defined and more stable against interactions than in one and two dimensions. We use a number of complementary definitions for a quasiparticle to examine the interacting spectral function, contrasting two-dimensional and three-dimensional situations critically.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.104.125118}, author = {Ahn, Seongjin and Das Sarma, Sankar} } @article {mueller_single-particle-like_2021, title = {From single-particle-like to interaction-mediated plasmonic resonances in graphene nanoantennas}, journal = {J. Appl. Phys.}, volume = {129}, number = {9}, year = {2021}, note = {Place: 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA Publisher: AMER INST PHYSICS Type: Article}, month = {mar}, abstract = {Plasmonic nanostructures attract tremendous attention as they confine electromagnetic fields well below the diffraction limit while simultaneously sustaining extreme local field enhancements. To fully exploit these properties, the identification and classification of resonances in such nanostructures is crucial. Recently, a novel figure of merit for resonance classification has been proposed [Muller et al., J. Phys. Chem. C 124, 24331-24343 (2020)] and its applicability was demonstrated mostly to toy model systems. This novel measure, the energy-based plasmonicity index (EPI), characterizes the nature of resonances in molecular nanostructures. The EPI distinguishes between either a single-particle-like or a plasmonic nature of resonances based on the energy space coherence dynamics of the excitation. To advance the further development of this newly established measure, we present here its exemplary application to characterize the resonances of graphene nanoantennas. In particular, we focus on resonances in a doped nanoantenna. The structure is of interest, as a consideration of the electron dynamics in real space might suggest a plasmonic nature of selected resonances in the low doping limit but our analysis reveals the opposite. We find that in the undoped and moderately doped nanoantenna, the EPI classifies all emerging resonances as predominantly single-particle-like, and only after doping the structure heavily, the EPI observes plasmonic response.}, issn = {0021-8979}, doi = {10.1063/5.0038883}, author = {Mueller, Marvin M. and Kosik, Miriam and Pelc, Marta and Bryant, Garnett W. and Ayuela, Andres and Rockstuhl, Carsten and Slowik, Karolina} } @article { WOS:000655905200002, title = {Generating function for tensor network diagrammatic summation}, journal = {Phys. Rev. B}, volume = {103}, number = {20}, year = {2021}, month = {MAY 28}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {The understanding of complex quantum many-body systems has been vastly boosted by tensor network (TN) methods. Among others, excitation spectrum and long-range interacting systems can be studied using TNs, where one however confronts the intricate summation over an extensive number of tensor diagrams. Here, we introduce a set of generating functions, which encode the diagrammatic summations as leading-order series expansion coefficients. Combined with automatic differentiation, the generating function allows us to solve the problem of TN diagrammatic summation. We illustrate this scheme by computing variational excited states and the dynamical structure factor of a quantum spin chain, and further investigating entanglement properties of excited states. Extensions to infinite-size systems and higher dimension are outlined.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.103.205155}, author = {Tu, Wei-Lin and Wu, Huan-Kuang and Schuch, Norbert and Kawashima, Naoki and Chen, Ji-Yao} } @article { WOS:000674695300001, title = {Geometrical Formalism for Dynamically Corrected Gates in Multiqubit Systems}, journal = {PRX Quantum}, volume = {2}, number = {1}, year = {2021}, month = {MAR 9}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {The ability to perform gates in multiqubit systems that are robust to noise is of crucial importance for the advancement of quantum information technologies. However, finding control pulses that cancel noise while performing a gate is made difficult by the intractability of the time-dependent Schrodinger equation, especially in multiqubit systems. Here, we show that this issue can be sidestepped by using a formalism in which the cumulative error during a gate is represented geometrically as a curve in a multidimensional Euclidean space. Cancelation of noise errors to leading order corresponds to closure of the curve, a condition that can be satisfied without solving the Schrodinger equation. We develop and uncover general properties of this geometric formalism, and derive a recursion relation that maps control fields to curvatures for Hamiltonians of arbitrary dimension. We demonstrate the utility of the formalism by employing it to design pulses that simultaneously correct against both noise errors and crosstalk for two qubits coupled by an Ising interaction. We give examples both of a single-qubit rotation and a two-qubit maximally entangling gate. The results obtained in this example are relevant to both superconducting transmon qubits and semiconductor quantum-dot spin qubits. We propose this geometric formalism as a general technique for pulse-induced error suppression in quantum computing gate operations.}, doi = {10.1103/PRXQuantum.2.010341}, author = {Buterakos, Donovan and Das Sarma, Sankar and Barnes, Edwin} } @article {green_how_2021, title = {How to profit from quantum technology without building quantum computers}, journal = {Nat. Rev. Phys.}, volume = {3}, number = {3}, year = {2021}, note = {Place: CAMPUS, 4 CRINAN ST, LONDON, N1 9XW, ENGLAND Publisher: SPRINGERNATURE Type: Editorial Material}, month = {mar}, pages = {150{\textendash}152}, abstract = {There are a number of lower risk opportunities to invest in quantum technologies, other than quantum computers, but to make the most of them both specialist knowledge and market awareness are required.}, doi = {10.1038/s42254-021-00290-w}, author = {Green, Dmitry and Soller, Henning and Oreg, Yuval and Galitski, Victor} } @article {briles_hybrid_2021, title = {Hybrid {InP} and {SiN} integration of an octave-spanning frequency comb}, journal = {APL Phontonics}, volume = {6}, number = {2}, year = {2021}, note = {Place: 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA Publisher: AMER INST PHYSICS Type: Article}, month = {feb}, abstract = {Implementing optical-frequency combs with integrated photonics will enable wider use of precision timing signals. Here, we explore the generation of an octave-span, Kerr-microresonator frequency comb using hybrid integration of an InP distributed-feedback laser and a SiN photonic-integrated circuit. We demonstrate electrically pumped and fiber-packaged prototype systems, enabled by self-injection locking. This direct integration of a laser and a microresonator circuit without previously used intervening elements, such as optical modulators and isolators, necessitates understanding self-injection-locking dynamics with octave-span Kerr solitons. In particular, system architectures must adjust to the strong coupling of microresonator backscattering and laser-microresonator frequency detuning that we uncover here. Our work illustrates critical considerations toward realizing a self-referenced frequency comb with integrated photonics.}, issn = {2378-0967}, doi = {10.1063/5.0035452}, author = {Briles, Travis C. and Yu, Su-Peng and Chang, Lin and Xiang, Chao and Guo, Joel and Kinghorn, David and Moille, Gregory and Srinivasan, Kartik and Bowers, John E. and Papp, Scott B.} } @article { WOS:000658132700032, title = {Hybridization of circular and rectangular transverse profiles of nanophotonic modes for nonlinear optics}, journal = {Opt. Lett.}, volume = {46}, number = {11}, year = {2021}, month = {JUN 1}, pages = {2682-2685}, publisher = {OPTICAL SOC AMER}, type = {Article}, abstract = {Nanophotonic modes within rectangular cross sections are typically considered to have transverse rectangular field profiles. In this work, we show that, despite the rectangular cross section of most integrated waveguides and microring resonators, there exists considerable hybridization of transverse rectangular modes and transverse circular modes. These hybridized modes can be advantageous in nonlinear wave mixing processes. We use third-harmonic generation as an example to confirm that such a hybridized mode is advantageous in combining reasonable mode overlap and waveguide coupling to a fundamental mode in a silicon nitride microring. Our work illuminates the potential of using transverse circular modes in nanophotonic applications. (C) 2021 Optical Society of America}, issn = {0146-9592}, doi = {10.1364/OL.426043}, author = {Lu, Xiyuan and Jiang, Wei C. and Srinivasan, Kartik} } @article { WOS:000646729500001, title = {Hydrodynamic sound and plasmons in three dimensions}, journal = {Phys. Rev. B}, volume = {103}, number = {15}, year = {2021}, month = {APR 1}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {In a recent paper by Lucas and Das Sarma {[}Phys. Rev. B 97. 115449 (2018)], a solvable model of collective modes in two-dimensional metals was considered in the hydrodynamic regime. In the current work, we generalize the hydrodynamic theory to three-dimensional (3D) metals for which the calculation of sound modes in a strongly coupled quantum Coulomb plasma can be made explicit. The specific theoretical question of interest is how the usual linearly dispersing hydrodynamic sound mode relates to the well-known gapped 3D plasmon collective mode in the presence of long-range Coulomb interaction. We show analytically that both the zero sound in the collisionless regime and the first sound in the hydrodynamic region become massive in three dimensions, acquiring a finite gap because of the long-range Coulomb interaction, while their damping rates become quadratic in momentum. We also discuss other types of long-range potential, where the dispersion of sound modes is modified accordingly. The general result is that the leading-order hydrodynamic sound mode is always given by the leading-order plasmon frequency in the presence of long-range Coulomb interaction, but the next-to-leading-order dispersion corrections differ in hydrodynamic and collisionless regimes.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.103.155101}, author = {Jian, Shao-Kai and Das Sarma, Sankar} } @article { WOS:000722896900048, title = {Impact of the precursor gas ratio on dispersion engineering of broadband silicon nitride microresonator frequency combs}, journal = {Opt. Lett.}, volume = {46}, number = {23}, year = {2021}, month = {DEC 1}, pages = {5970-5973}, publisher = {OPTICAL SOC AMER}, type = {Article}, abstract = {Microresonator frequency combs, or microcombs, have gained wide appeal for their rich nonlinear physics and wide range of applications. Stoichiometric silicon nitride films grown via low-pressure chemical vapor deposition (LPCVD), in particular, are widely used in chip-integrated Kerr microcombs. Critical to such devices is the ability to control the microresonator dispersion, which has contributions from both material refractive index dispersion and geometric confinement. Here, we show that modifications to the ratio of the gaseous precursors in LPCVD growth have a significant impact on material dispersion and hence the overall microresonator dispersion. In contrast to the many efforts focused on comparisons between Si-rich films and stoichiometric (Si3N4) films, here, we focus on films whose precursor gas ratios should nominally place them in the stoichiometric regime. We further show that microresonator geometric dispersion can be tuned to compensate for changes in the material dispersion. (C) 2021 Optical Society of America.}, issn = {0146-9592}, doi = {10.1364/OL.440907}, author = {Moille, Gregory and Westly, Daron and Simelgor, Gregory and Srinivasan, Kartik} } @article { WOS:000688553600007, title = {Interaction-Driven Filling-Induced Metal-Insulator Transitions in 2D Moire Lattices}, journal = {Phys. Rev. Lett.}, volume = {127}, number = {9}, year = {2021}, month = {AUG 24}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Using a realistic band structure for twisted WSe2 materials, we develop a theory for the interaction-driven correlated insulators to conducting metals transitions through the tuning of the filling factor around commensurate fractional fillings of the moire unit cell in the 2D honeycomb lattice, focusing on the dominant half-filled Mott insulating state, which exists for both long- and short-range interactions. We find metallic states slightly away from half-filling, as have recently been observed experimentally. We discuss the stabilities and the magnetic properties of the resulting insulating and metallic phases, and comment on their experimental signatures. We also discuss the nature of the correlated insulator states at the rational fractional fillings.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.127.096802}, author = {Pan, Haining and Das Sarma, Sankar} } @article { WOS:000652826500009, title = {Intrinsic Time-Reversal-Invariant Topological Superconductivity in Thin Films of Iron-Based Superconductors}, journal = {Phys. Rev. Lett.}, volume = {126}, number = {13}, year = {2021}, month = {MAR 30}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We establish quasi-two-dimensional thin films of iron-based superconductors (FeSCs) as a new hightemperature platform for hosting intrinsic time-reversal-invariant helical topological superconductivity (TSC). Based on the combination of Dirac surface state and bulk extended s-wave pairing, our theory should be directly applicable to a large class of experimentally established FeSCs, opening a new TSC paradigm. In particular, an applied electric field serves as a {\textquoteleft}{\textquoteleft}topological switch{{\textquoteright}{\textquoteright}} for helical Majorana edge modes in FeSC thin films, allowing for an experimentally feasible design of gate-controlled helical Majorana circuits. Applying an in-plane magnetic field drives the helical TSC phase into a higher-order TSC carrying corner-localized Majorana zero modes. Our proposal should enable the experimental realization of helical Majorana fermions.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.126.137001}, author = {Zhang, Rui-Xing and Das Sarma, S.} } @article { WOS:000735454800019, title = {Know the enemy: 2D Fermi liquids}, journal = {Ann. Phys.}, volume = {435}, number = {2, SI}, year = {2021}, month = {DEC}, publisher = {ACADEMIC PRESS INC ELSEVIER SCIENCE}, type = {Article}, abstract = {We describe an analytical theory investigating the regime of validity of the Fermi liquid theory in interacting, via the long-range Coulomb coupling, two-dimensional Fermi systems comparing it with the corresponding 3D systems. We find that the 2D Fermi liquid theory and 2D quasiparticles are robust up to high energies and temperatures of the order of Fermi energy above the Fermi surface, very similar to the corresponding three-dimensional situation. We calculate the phase diagram in the frequency- temperature space separating the collisionless ballistic regime and the collision-dominated hydrodynamic regime for 2D and 3D interacting electron systems. We also provide the temperature corrections up to third order for the renormalized effective mass, and comment on the validity of 2D Wiedemann-Franz law and 2D Kadawoki-Woods relation. (c) 2021 Elsevier Inc. All rights reserved.}, keywords = {Electron self-energy, Fermi liquid, Random phase approximation}, issn = {0003-4916}, doi = {10.1016/j.aop.2021.168495}, author = {Das Sarma, Sankar and Liao, Yunxiang} } @article { WOS:000709549100048, title = {Local Control of Supercurrent Density in Epitaxial Planar Josephson Junctions}, journal = {Nano Lett.}, volume = {21}, number = {19}, year = {2021}, month = {OCT 13}, pages = {8274-8280}, publisher = {AMER CHEMICAL SOC}, type = {Article}, abstract = {The critical current response to an applied out-of- plane magnetic field in a Josephson junction provides insight into the uniformity of its current distribution. In Josephson junctions with semiconducting weak links, the carrier density, and therefore the overall current distribution, can be modified electrostatically via metallic gates. Here, we show local control of the current distribution in an epitaxial Al-InAs Josephson junction equipped with five minigates. We demonstrate that not only can the junction width be electrostatically defined but also the current profile can be locally adjusted to form superconducting quantum interference devices. Our studies show enhanced edge conduction in such long junctions, which can be eliminated by minigates to create a uniform current distribution.}, keywords = {band-bending effects, electrostatic gates, Josephson junction, supercurrent distribution}, issn = {1530-6984}, doi = {10.1021/acs.nanolett.1c02771}, author = {Elfeky, Bassel Heiba and Lotfizadeh, Neda and Schiela, William F. and Strickland, William M. and Dartiailh, Matthieu and Sardashti, Kasra and Hatefipour, Mehdi and Yu, Peng and Pankratova, Natalia and Lee, Hanho and Manucharyan, Vladimir E. and Shabani, Javad} } @article {seif_machine_2021, title = {Machine learning the thermodynamic arrow of time}, journal = {Nat. Phys.}, volume = {17}, number = {1}, year = {2021}, note = {Place: HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY Publisher: NATURE RESEARCH Type: Article}, month = {jan}, abstract = {The asymmetry in the flow of events that is expressed by the phrase {\textquoteleft}time{\textquoteright}s arrow{\textquoteright} traces back to the second law of thermodynamics. In the microscopic regime, fluctuations prevent us from discerning the direction of time{\textquoteright}s arrow with certainty. Here, we find that a machine learning algorithm that is trained to infer the direction of time{\textquoteright}s arrow identifies entropy production as the relevant physical quantity in its decision-making process. Effectively, the algorithm rediscovers the fluctuation theorem as the underlying thermodynamic principle. Our results indicate that machine learning techniques can be used to study systems that are out of equilibrium, and ultimately to answer open questions and uncover physical principles in thermodynamics. The phrase {\textquoteleft}arrow of time{\textquoteright} refers to the asymmetry in the flow of events. A machine learning algorithm trained to infer its direction identifies entropy production as the relevant underlying physical principle in the decision-making process.}, issn = {1745-2473}, doi = {10.1038/s41567-020-1018-2}, author = {Seif, Alireza and Hafezi, Mohammad and Jarzynski, Christopher} } @article { WOS:000663144400001, title = {Machine-learning enhanced dark soliton detection in Bose-Einstein condensates}, journal = {Mach. Learn.-Sci. Technol.}, volume = {2}, number = {3}, year = {2021}, month = {SEP}, publisher = {IOP PUBLISHING LTD}, type = {Article}, abstract = {Most data in cold-atom experiments comes from images, the analysis of which is limited by our preconceptions of the patterns that could be present in the data. We focus on the well-defined case of detecting dark solitons-appearing as local density depletions in a Bose-Einstein condensate (BEC)-using a methodology that is extensible to the general task of pattern recognition in images of cold atoms. Studying soliton dynamics over a wide range of parameters requires the analysis of large datasets, making the existing human-inspection-based methodology a significant bottleneck. Here we describe an automated classification and positioning system for identifying localized excitations in atomic BECs utilizing deep convolutional neural networks to eliminate the need for human image examination. Furthermore, we openly publish our labeled dataset of dark solitons, the first of its kind, for further machine learning research.}, keywords = {convolutional neural network, dark solitons, machine learning}, doi = {10.1088/2632-2153/abed1e}, author = {Guo, Shangjie and Fritsch, Amilson R. and Greenberg, Craig and Spielman, I. B. and Zwolak, Justyna P.} } @article {wang_magnetotransport_2021, title = {Magnetotransport in hybrid {InSe}/monolayer graphene on {SiC}}, journal = {Nanotechnology}, volume = {32}, number = {15}, year = {2021}, note = {Place: TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND Publisher: IOP PUBLISHING LTD Type: Article}, month = {apr}, abstract = {The magnetotransport properties of a hybrid InSe/monolayer graphene in a SiC system are systematically studied. Compared to those of its bare graphene counterpart, in InSe/graphene, we can effectively modify the carrier density, mobility, effective mass, and electron-electron (e-e) interactions enhanced by weak disorder. We show that in bare graphene and hybrid InSe/graphene systems, the logarithmic temperature (lnT) dependence of the Hall slope R-H = delta R-xy/delta B = delta rho(xy)/delta B can be used to probe e-e interaction effects at various temperatures even when the measured resistivity does not show a lnT dependence due to strong electron-phonon scattering. Nevertheless, one needs to be certain that the change of R-H is not caused by an increase of the carrier density by checking the magnetic field position of the longitudinal resistivity minimum at different temperatures. Given the current challenges in gating graphene on SiC with a suitable dielectric layer, our results suggest that capping a van der Waals material on graphene is an effective way to modify the electronic properties of monolayer graphene on SiC.

}, keywords = {graphene, Hall effect, InSe, interactions}, issn = {0957-4484}, doi = {10.1088/1361-6528/abd726}, author = {Wang, Chih-Yuan and Lin, Yun-Wu and Chuang, Chiashain and Yang, Cheng-Hsueh and Patel, Dinesh K. and Chen, Sheng-Zong and Yeh, Ching-Chen and Chen, Wei-Chen and Lin, Chia-Chun and Chen, Yi-Hsun and Wang, Wei-Hua and Sankar, Raman and Chou, Fang-Cheng and Kruskopf, Mattias and Elmquist, Randolph E. and Liang, Chi-Te} } @article { WOS:000707419400006, title = {Manipulating atom-number distributions and detecting spatial distributions in lattice-confined spinor gases}, journal = {Phys. Rev. A}, volume = {104}, number = {4}, year = {2021}, month = {OCT 15}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We present an experimental study demonstrating the manipulation of atom-number distributions of spinor gases after nonequilibrium quantum quenches across superfluid to Mott-insulator phase transitions in cubic optical lattices. Our data indicate that atom distributions in individual Mott lobes can be tuned by properly designing quantum quench sequences, which suggests methods of maximizing the fraction of atoms in Mott lobes of even occupation numbers and has applications in attaining different quantum magnetic phases including massively entangled states. Spatial distributions of gases in three-dimensional lattices are derived from the observed number distributions, which reveal complex spatial dynamics during the quantum quenches. Qualitative agreements are also found between our experimental data and numerical simulations based on time-dependent Gutzwiller approximations in two-dimensional systems.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.104.L041304}, author = {Austin, J. O. and Shaw, Z. N. and Chen, Z. and Mahmud, K. W. and Liu, Y.} } @article { WOS:000704691400003, title = {Measurement-Induced Phase Transition in the Monitored Sachdev-Ye-Kitaev Model}, journal = {Phys. Rev. Lett.}, volume = {127}, number = {14}, year = {2021}, month = {SEP 27}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We construct Brownian Sachdev-Ye-Kitaev (SYK) chains subjected to continuous monitoring and explore possible entanglement phase transitions therein. We analytically derive the effective action in the large-N limit and show that an entanglement transition is caused by the symmetry breaking in the enlarged replica space. In the noninteracting case with SYK2 chains, the model features a continuous O(2) symmetry between two replicas and a transition corresponding to spontaneous breaking of that symmetry upon varying the measurement rate. In the symmetry broken phase at low measurement rate, the emergent replica criticality associated with the Goldstone mode leads to a log-scaling entanglement entropy that can be attributed to the free energy of vortices. In the symmetric phase at higher measurement rate, the entanglement entropy obeys area-law scaling. In the interacting case, the continuous O(2) symmetry is explicitly lowered to a discrete C-4 symmetry, giving rise to volume-law entanglement entropy in the symmetry-broken phase due to the enhanced linear free energy cost of domain walls compared to vortices. The interacting transition is described by C-4 symmetry breaking. We also verify the large-N critical exponents by numerically solving the Schwinger-Dyson equation.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.127.140601}, author = {Jian, Shao-Kai and Liu, Chunxiao and Chen, Xiao and Swingle, Brian and Zhang, Pengfei} } @article {carney_mechanical_2021, title = {Mechanical quantum sensing in the search for dark matter}, journal = {Quantum Sci. Technol.}, volume = {6}, number = {2}, year = {2021}, note = {Place: TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND Publisher: IOP PUBLISHING LTD Type: Article}, month = {apr}, abstract = {Numerous astrophysical and cosmological observations are best explained by the existence of dark matter, a mass density which interacts only very weakly with visible, baryonic matter. Searching for the extremely weak signals produced by this dark matter strongly motivate the development of new, ultra-sensitive detector technologies. Paradigmatic advances in the control and readout of massive mechanical systems, in both the classical and quantum regimes, have enabled unprecedented levels of sensitivity. In this white paper, we outline recent ideas in the potential use of a range of solid-state mechanical sensing technologies to aid in the search for dark matter in a number of energy scales and with a variety of coupling mechanisms.}, keywords = {dark matter, Optomechanics, quantum sensing, standard quantum limits}, issn = {2058-9565}, doi = {10.1088/2058-9565/abcfcd}, author = {Carney, D. and Krnjaic, G. and Moore, D. C. and Regal, C. A. and Afek, G. and Bhave, S. and Brubaker, B. and Corbitt, T. and Cripe, J. and Crisosto, N. and Geraci, A. and Ghosh, S. and Harris, J. G. E. and Hook, A. and Kolb, E. W. and Kunjummen, J. and Lang, R. F. and Li, T. and Lin, T. and Liu, Z. and Lykken, J. and Magrini, L. and Manley, J. and Matsumoto, N. and Monte, A. and Monteiro, F. and Purdy, T. and Riedel, C. J. and Singh, R. and Singh, S. and Sinha, K. and Taylor, J. M. and Qin, J. and Wilson, D. J. and Zhao, Y.} } @article {yang_momentum_2021, title = {Momentum space toroidal moment in a photonic metamaterial}, journal = {Nat. Commun.}, volume = {12}, number = {1}, year = {2021}, note = {Place: HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY Publisher: NATURE RESEARCH Type: Article}, month = {mar}, abstract = {Berry curvature, the counterpart of the magnetic field in the momentum space, plays a vital role in the transport of electrons in condensed matter physics. It also lays the foundation for the emerging field of topological physics. In the three-dimensional systems, much attention has been paid to Weyl points, which serve as sources and drains of Berry curvature. Here, we demonstrate a toroidal moment of Berry curvature with flux approaching to in judiciously engineered metamaterials. The Berry curvature exhibits a vortex-like configuration without any source and drain in the momentum space. Experimentally, the presence of Berry curvature toroid is confirmed by the observation of conical-frustum shaped domain-wall states at the interfaces formed by two metamaterials with opposite toroidal moments. The appearance of toroidal multipolar moments in electrodynamics interrogates the question for their existence in Berry curvature, which can be seen as the {\textquotedblleft}magnetic field{\textquotedblright} in the momentum space. Here, the authors observe 3D vortex distributions in the Berry curvature within a photonic metamaterial.}, issn = {2041-1723}, doi = {10.1038/s41467-021-22063-w}, author = {Yang, Biao and Bi, Yangang and Zhang, Rui-Xing and Zhang, Ruo-Yang and You, Oubo and Zhu, Zhihong and Feng, Jing and Sun, Hongbo and Chan, C. T. and Liu, Chao-Xing and Zhang, Shuang} } @article { WOS:000654369300091, title = {Multiple-camera defocus imaging of ultracold atomic gases}, journal = {Opt. Express}, volume = {29}, number = {11}, year = {2021}, month = {MAY 24}, pages = {17029-17041}, publisher = {OPTICAL SOC AMER}, type = {Article}, abstract = {In cold atom experiments, each image of light refracted and absorbed by an atomic ensemble carries a remarkable amount of information. Numerous imaging techniques including absorption, fluorescence, and phase-contrast are commonly used. Other techniques such as off-resonance defocused imaging (ORDI, {[}1-4]), where an in-focus image is deconvolved from a defocused image, have been demonstrated but find only niche applications. The ORDI inversion process introduces systematic artifacts because it relies on regularization to account for missing information at some spatial frequencies. In the present work, we extend ORDI to use multiple cameras simultaneously at degrees of defocus, eliminating the need for regularization and its attendant artifacts. We demonstrate this technique by imaging Bose-Einstein condensates, and show that the statistical uncertainties in the measured column density using the multiple-camera off-resonance defocused (McORD) imaging method are competitive with absorption imaging near resonance and phase contrast imaging far from resonance. Experimentally, the McORD method may be incorporated into existing set-ups with minimal additional equipment. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement}, issn = {1094-4087}, doi = {10.1364/OE.422981}, author = {Perry, A. R. and Sugawa, S. and Salces-Carcoba, F. and Yue, Y. and Spielman, I. B.} } @article { WOS:000685620700001, title = {Nanoscale Positioning Approaches for Integrating Single Solid-State Quantum Emitters with Photonic Nanostructures}, journal = {Laser Photon. Rev.}, volume = {15}, number = {10}, year = {2021}, month = {OCT}, publisher = {WILEY-V C H VERLAG GMBH}, type = {Review}, abstract = {Deterministically integrating single solid-state quantum emitters with photonic nanostructures serves as a key enabling resource in the context of photonic quantum technology. Due to the random spatial location of many widely-used solid-state quantum emitters, a number of positioning approaches for locating the quantum emitters before nanofabrication have been explored in the last decade. Here, the working principles of several nanoscale positioning methods and the most recent progress in this field, covering techniques including atomic force microscopy, scanning electron microscopy, confocal microscopy with in situ lithography, and wide-field fluorescence imaging are reviewed. A selection of representative device demonstrations with high-performance is presented, including high-quality single-photon sources, bright entangled-photon pairs, strongly-coupled cavity QED systems, and other emerging applications. The challenges in applying positioning techniques to different material systems and opportunities for using these approaches for realizing large-scale quantum photonic devices are discussed.}, keywords = {deterministic coupling, epitaxial quantum dots, photonic nanostructures}, issn = {1863-8880}, doi = {10.1002/lpor.202100223}, author = {Liu, Shunfa and Srinivasan, Kartik and Liu, Jin} } @article {jian_note_2021, title = {Note on entropy dynamics in the {Brownian} {SYK} model}, journal = {J. High Energy Phys.}, number = {3}, year = {2021}, note = {Place: ONE NEW YORK PLAZA, SUITE 4600, NEW YORK, NY, UNITED STATES Publisher: SPRINGER Type: Article}, month = {mar}, abstract = {We study the time evolution of Renyi entropy in a system of two coupled Brownian SYK clusters evolving from an initial product state. The Renyi entropy of one cluster grows linearly and then saturates to the coarse grained entropy. This Page curve is obtained by two different methods, a path integral saddle point analysis and an operator dynamics analysis. Using the Brownian character of the dynamics, we derive a master equation which controls the operator dynamics and gives the Page curve for purity. Insight into the physics of this complicated master equation is provided by a complementary path integral method: replica diagonal and non-diagonal saddles are responsible for the linear growth and saturation of Renyi entropy, respectively.}, keywords = {AdS-CFT Correspondence, Black Holes, Nonperturbative Effects, Random Systems}, issn = {1029-8479}, doi = {10.1007/JHEP03(2021)042}, author = {Jian, Shao-Kai and Swingle, Brian} } @article {walter_observation_2021, title = {Observation of an {Electric} {Quadrupole} {Transition} in a {Negative} {Ion}: {Experiment} and {Theory}}, journal = {Phys. Rev. Lett.}, volume = {126}, number = {8}, year = {2021}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, abstract = {The first direct experimental observation of an electric quadrupole (E2) absorption transition between bound states of an atomic negative ion has been made. The transition was observed in the negative ion of bismuth by resonant (1 + 1) photon detachment from Bi- via P-3(2) -{\textgreater} P-3(0) excitation. The E2 transition properties were completely independently calculated using a hybrid theoretical approach to account for the strong multilevel electron interactions and relativistic effects. The experimental and ab initio theoretical results are in excellent agreement, providing valuable new insight into this complex system and forbidden transitions in negative ions more generally.

}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.126.083001}, author = {Walter, C. W. and Spielman, S. E. and Ponce, R. and Gibson, N. D. and Yukich, J. N. and Cheung, C. and Safronova, M. S.} } @article { WOS:000685113600007, title = {Observation of Vacuum-Induced Collective Quantum Beats}, journal = {Phys. Rev. Lett.}, volume = {127}, number = {7}, year = {2021}, month = {AUG 13}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We demonstrate collectively enhanced vacuum-induced quantum beat dynamics from a three-level V-type atomic system. Exciting a dilute atomic gas of magneto-optically trapped Rb-85 atoms with a weak drive resonant on one of the transitions, we observe the forward-scattered field after a sudden shut-off of the laser. The subsequent radiative dynamics, measured for various optical depths of the atomic cloud, exhibits superradiant decay rates, as well as collectively enhanced quantum beats. Our work is also the first experimental illustration of quantum beats arising from atoms initially prepared in a single excited level as a result of the vacuum-induced coupling between excited levels.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.127.073604}, author = {Han, Hyok Sang and Lee, Ahreum and Sinha, Kanupriya and Fatemi, Fredrik K. and Rolston, S. L.} } @article { WOS:000668996900008, title = {Optical flux pump in the quantum Hall regime}, journal = {Phys. Rev. B}, volume = {103}, number = {24}, year = {2021}, month = {JUN 28}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {A seminal gedankenexperiment by Laughlin describes the charge transport in quantum Hall systems via the pumping of flux. Here, we propose an optical scheme which probes and manipulates quantum Hall systems in a similar way: When light containing orbital angular momentum interacts with electronic Landau levels, it acts as a flux pump which radially moves the electrons through the sample. We investigate this effect for a graphene system with Corbino geometry and calculate the radial current in the absence of any electric potential bias. Remarkably, the current is robust against the disorder which is consistent with the lattice symmetry, and in the weak excitation limit, the current shows a power-law scaling with intensity characterized by the novel exponent 2/3.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.103.L241301}, author = {Cao, Bin and Grass, Tobias and Solomon, Glenn and Hafezi, Mohammad} } @article {19231, title = {Optimal control for quantum detectors}, journal = {npj Quantum Information}, volume = {7}, year = {2021}, month = {03/2021}, abstract = {Quantum systems are promising candidates for sensing of weak signals as they can be highly sensitive to external perturbations, thus providing excellent performance when estimating parameters of external fields. However, when trying to detect weak signals that are hidden by background noise, the signal-to-noise ratio is a more relevant metric than raw sensitivity. We identify, under modest assumptions about the statistical properties of the signal and noise, the optimal quantum control to detect an external signal in the presence of background noise using a quantum sensor. Interestingly, for white background noise, the optimal solution is the simple and well-known spin-locking control scheme. Using numerical techniques, we further generalize these results to the case of background noise with a Lorentzian spectrum. We show that for increasing correlation time, pulse based sequences, such as CPMG, are also close to the optimal control for detecting the signal, with the crossover dependent on the signal frequency. These results show that an optimal detection scheme can be easily implemented in near-term quantum sensors without the need for complicated pulse shaping.

}, doi = {10.1038/s41534-021-00383-5}, url = {https://doi.org/10.1038/s41534-021-00383-5}, author = {Paraj Titum and Kevin Schultz and Alireza Seif and Gregory Quiroz and B. D. Clader} } @article {safronova_predicting_2021, title = {Predicting quasibound states of negative ions: {La}- as a test case}, journal = {Phys. Rev. A}, volume = {103}, number = {2}, year = {2021}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {feb}, abstract = {We demonstrated the accurate prediction of a quasibound spectrum of a negative ion using a high-precision theoretical approach. We used La as a test case due to a recent experiment that measured energies of 11 resonances in its photodetachment spectrum attributed to transitions to quasibound states [Phys. Rev. A 102, 042812 (2020)]. We identified all of the observed resonances and predicted one more peak just outside the range of the prior experiment. Following the theoretical prediction, the peak was observed at the predicted wavelength, validating the identification. The same approach is applicable to a wide range of negative ions.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.103.022819}, author = {Safronova, M. S. and Cheung, C. and Kozlov, M. G. and Spielman, S. E. and Gibson, N. D. and Walter, C. W.} } @article { WOS:000655905200001, title = {Presence versus absence of two-dimensional Fermi surface anomalies}, journal = {Phys. Rev. B}, volume = {103}, number = {20}, year = {2021}, month = {MAY 28}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We theoretically consider Fermi surface anomalies manifesting in the temperature-dependent quasiparticle properties of two-dimensional (2D) interacting electron systems, comparing and contrasting with the corresponding three-dimensional (3D) Fermi liquid situation. In particular, employing microscopic many-body perturbative techniques, we obtain analytically the leading-order and the next-to-leading-order interaction corrections to the renormalized effective mass for three distinct physical interaction models: electron-phonon, electron-paramagnon, and electron-electron Coulomb coupling. We find that the 2D renormalized effective mass does not develop any Fermi surface anomaly due to electron-phonon interaction, manifesting O(T-2) temperature correction and thus remaining consistent with the Sommerfeld expansion of the noninteracting Fermi function, in contrast to the corresponding 3D situation where the temperature correction to the renormalized effective mass has the anomalous T-2 log T behavior. In contrast, both electron-paramagnon and electron-electron interactions lead to the anomalous O(T) corrections to the 2D effective mass renormalization in contrast to T-2 log T behavior in the corresponding 3D interacting systems. We provide detailed analytical results, and comment on the conditions under which a T-2 log T term could possibly arise in the 2D quasiparticle effective mass from electron-phonon interactions. We also compare results for the temperature-dependent specific heat in the interacting 2D and 3D Fermi systems, using the close connection between the effective mass and specific heat.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.103.205154}, author = {Buterakos, Donovan and DinhDuy Vu and Yu, Jiabin and Das Sarma, Sankar} } @article { WOS:000705661700006, title = {Probing open- and closed-channel p-wave resonances}, journal = {Phys. Rev. Res.}, volume = {3}, number = {3}, year = {2021}, month = {SEP 20}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We study the near-threshold molecular and collisional physics of a strong K-40 p-wave Feshbach resonance through a combination of measurements, numerical calculations, and modeling. Dimer spectroscopy employs both radio-frequency spin-flip association in the MHz band and resonant association in the kHz band. Systematic uncertainty in the measured binding energy is reduced by a model that includes both the Franck-Condon overlap amplitude and inhomogeneous broadening. Coupled-channels calculations based on mass-scaled K-39 potentials compare well to the observed binding energies and also reveal a low-energy p-wave shape resonance in the open channel. Contrary to conventional expectation, we observe a nonlinear variation of the binding energy with magnetic field, and explain how this arises from the interplay of the closed-channel ramping state with the near-threshold shape resonance in the open channel. We develop an analytic two-channel model that includes both resonances as well as the dipole-dipole interactions which, we show, become important at low energy. Using this parametrization of the energy dependence of the scattering phase, we can classify the studied K-40 resonance as broad. Throughout the paper, we compare to the well-understood s-wave case and discuss the significant role played by van der Waals physics. The resulting understanding of the dimer physics of p-wave resonances provides a solid foundation for future exploration of few- and many-body orbital physics.}, doi = {10.1103/PhysRevResearch.3.033269}, author = {Ahmed-Braun, Denise J. M. and Jackson, Kenneth G. and Smale, Scott and Dale, Colin J. and Olsen, Ben A. and Kokkelmans, Servaas J. J. M. F. and Julienne, Paul S. and Thywissen, Joseph H.} } @article { WOS:000655978400001, title = {Programmable quantum simulations of spin systems with trapped ions}, journal = {Rev. Mod. Phys.}, volume = {93}, number = {2}, year = {2021}, month = {APR 7}, publisher = {AMER PHYSICAL SOC}, type = {Review}, abstract = {Laser-cooled and trapped atomic ions form an ideal standard for the simulation of interacting quantum spin models. Effective spins are represented by appropriate internal energy levels within each ion, and the spins can be measured with near-perfect efficiency using state-dependent fluorescence techniques. By applying optical fields that exert optical dipole forces on the ions, their Coulomb interaction can be modulated to produce long-range and tunable spin-spin interactions that can be reconfigured by shaping the spectrum and pattern of the laser fields in a prototypical example of a quantum simulator. Here the theoretical mapping of atomic ions to interacting spin systems, the preparation of complex equilibrium states, and the study of dynamical processes in these many-body interacting quantum systems are reviewed, and the use of this platform for optimization and other tasks is discussed. The use of such quantum simulators for studying spin models may inform our understanding of exotic quantum materials and shed light on the behavior of interacting quantum systems that cannot be modeled with conventional computers.}, issn = {0034-6861}, doi = {10.1103/RevModPhys.93.025001}, author = {Monroe, C. and Campbell, W. C. and Duan, L-M and Gong, Z-X and Gorshkov, V, A. and Hess, P. W. and Islam, R. and Kim, K. and Linke, N. M. and Pagano, G. and Richerme, P. and Senko, C. and Yao, N. Y.} } @article { WOS:000692128200001, title = {Programmable system on chip for controlling an atomic physics experiment}, journal = {Rev. Sci. Instrum.}, volume = {92}, number = {5}, year = {2021}, month = {MAY 1}, publisher = {AIP Publishing}, type = {Article}, abstract = {Most atomic physics experiments are controlled by a digital pattern generator used to synchronize all equipment by providing triggers and clocks. Recently, the availability of well-documented open-source development tools has lifted the barriers to using programmable systems on chip (PSoCs), making them a convenient and versatile tool for synthesizing digital patterns. Here, we take advantage of these advancements in the design of a versatile clock and pattern generator using a PSoC. We present our design with the intent of highlighting the new possibilities that PSoCs have to offer in terms of flexibility. We provide a robust hardware carrier and basic firmware implementation that can be expanded and modified for other uses. Published under license by AIP Publishing.}, issn = {0034-6748}, doi = {10.1063/5.0047535}, author = {Sitaram, A. and Campbell, G. K. and Restelli, A.} } @article {lu_proposal_2021, title = {Proposal for noise-free visible-telecom quantum frequency conversion through third-order sum and difference frequency generation}, journal = {Opt. Lett.}, volume = {46}, number = {2}, year = {2021}, note = {Place: 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA Publisher: OPTICAL SOC AMER Type: Article}, month = {jan}, pages = {222{\textendash}225}, abstract = {Quantum frequency conversion (QFC) between the visible and telecom is a key to connect quantum memories in fiber-based quantum networks. Current methods for linking such widely separated frequencies, such as sum/difference frequency generation and four-wave mixing Bragg scattering, are prone to broadband noise generated by the pump laser(s). To address this issue, we propose to use third-order sum/difference frequency generation (TSFG/TDFG) for an upconversion/downconversion QFC interface. In this process, two long wavelength pump photons combine their energy and momentum to mediate frequency conversion across the large spectral gap between the visible and telecom bands, which is particularly beneficial from the noise perspective. We show that waveguide-coupled silicon nitride microring resonators can be designed for efficient QFC between 606 and 1550 nm via a 1990 nm pump through TSFG/TDFG. We simulate the device dispersion and coupling, and from the simulated parameters, estimate that the frequency conversion can be efficient ({\textgreater}80\%) at 50 mW pump power. Our results suggest that microresonator TSFG/TDFG is promising for compact, scalable, and low-power QFC across large spectral gaps. (C) 2021 Optical Society of America}, issn = {0146-9592}, doi = {10.1364/OL.412602}, author = {Lu, Xiyuan and Moille, Gregory and Rao, Ashutosh and Srinivasan, Kartik} } @article { WOS:000662078500026, title = {Purcell-Enhanced Single Photon Source Based on a Deterministically Placed WSe2 Monolayer Quantum Dot in a Circular Bragg Grating Cavity}, journal = {Nano Lett.}, volume = {21}, number = {11}, year = {2021}, month = {JUN 9}, pages = {4715-4720}, publisher = {AMER CHEMICAL SOC}, type = {Article}, abstract = {We demonstrate a deterministic Purcell-enhanced single photon source realized by integrating an atomically thin WSe2 layer with a circular Bragg grating cavity. The cavity significantly enhances the photoluminescence from the atomically thin layer and supports single photon generation with g((2)) (0) < 0.25. We observe a consistent increase of the spontaneous emission rate for WSe2 emitters located in the center of the Bragg grating cavity. These WSe2 emitters are self-aligned and deterministically coupled to such a broadband cavity, configuring a new generation of deterministic single photon sources, characterized by their simple and low-cost production and intrinsic scalability.}, keywords = {bullseyes cavities, Purcell effect, Quantum Dots, single photons, two-dimensional materials}, issn = {1530-6984}, doi = {10.1021/acs.nanolett.1c00978}, author = {Iff, Oliver and Buchinger, Quirin and Moczala-Dusanowska, Magdalena and Kamp, Martin and Betzold, Simon and Davanco, Marcelo and Srinivasan, Kartik and Tongay, Sefaattin and Anton-Solanas, Carlos and Hoefling, Sven and Schneider, Christian} } @article { WOS:000657121500011, title = {Quantized and unquantized zero-bias tunneling conductance peaks in Majorana nanowires: Conductance below and above 2e(2)/h}, journal = {Phys. Rev. B}, volume = {103}, number = {21}, year = {2021}, month = {JUN 1}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Majorana zero modes can appear at the wire ends of a one-dimensional topological superconductor and manifest themselves as a quantized zero-bias conductance peak in the tunneling spectroscopy of normal-superconductor junctions. However, in superconductor-semiconductor hybrid nanowires, zero-bias conductance peaks may arise owing to topologically trivial mechanisms as well, mimicking the Majorana-induced topological peak in many aspects. In this work, we systematically investigate the characteristics of zero-bias conductance peaks for topological Majorana bound states, trivial quasi-Majorana bound states and low-energy Andreev bound states arising from smooth potential variations and disorder-induced subgap bound states. Our focus is on the conductance peak value (i.e., equal to, greater than, or less than 2e(2)/h), as well as the robustness (plateau- or spike-like) against the tuning parameters (e.g., the magnetic field and tunneling gate voltage) for zero-bias peaks arising from the different mechanisms. We find that for Majoranas and quasi-Majoranas, the zero-bias peak values are no more than 2e(2)/h, and a quantized conductance plateau forms generically as a function of parameters. By contrast, for conductance peaks due to low-energy Andreev bound states or disorder-induced bound states, the peak values may exceed 2e(2)/h, and a conductance plateau is rarely observed unless through careful postselection and fine-tuning. Our findings should shed light on the interpretation of experimental measurements on the tunneling spectroscopy of normal-superconductor junctions of hybrid Majorana nanowires.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.103.214502}, author = {Pan, Haining and Liu, Chun-Xiao and Wimmer, Michael and Das Sarma, Sankar} } @article {norrgard_quantum_2021, title = {Quantum blackbody thermometry}, journal = {New J. Phys.}, volume = {23}, number = {3}, year = {2021}, note = {Place: TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND Publisher: IOP PUBLISHING LTD Type: Article}, month = {mar}, abstract = {Blackbody radiation sources are calculable radiation sources that are frequently used in radiometry, temperature dissemination, and remote sensing. Despite their ubiquity, blackbody sources and radiometers have a plethora of systematics. We envision a new, primary route to measuring blackbody radiation using ensembles of polarizable quantum systems, such as Rydberg atoms and diatomic molecules. Quantum measurements with these exquisite electric field sensors could enable active feedback, improved design, and, ultimately, lower radiometric and thermal uncertainties of blackbody standards. A portable, calibration-free Rydberg-atom physics package could also complement a variety of classical radiation detector and thermometers. The successful merger of quantum and blackbody-based measurements provides a new, fundamental paradigm for blackbody physics.}, keywords = {blackbody radiation, laser cooling molecules, quantum metrology, Rydberg atoms}, issn = {1367-2630}, doi = {10.1088/1367-2630/abe8f5}, author = {Norrgard, Eric B. and Eckel, Stephen P. and Holloway, Christopher L. and Shirley, Eric L.} } @article { WOS:000726704700012, title = {Quantum circuits for the realization of equivalent forms of one-dimensional discrete-time quantum walks on near-term quantum hardware}, journal = {Phys. Rev. A}, volume = {104}, number = {6}, year = {2021}, month = {DEC 1}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Quantum walks are a promising framework for developing quantum algorithms and quantum simulations. They represent an important test case for the application of quantum computers. Here we present different forms of discrete-time quantum walks (DTQWs) and show their equivalence for physical realizations. Using an appropriate digital mapping of the position space on which a walker evolves to the multiqubit states of a quantum processor, we present different configurations of quantum circuits for the implementation of DTQWs in one-dimensional position space. We provide example circuits for a five-qubit processor and address scalability to higher dimensions as well as larger quantum processors.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.104.062401}, author = {Singh, Shivani and Alderete, C. Huerta and Balu, Radhakrishnan and Monroe, Christopher and Linke, Norbert M. and Chandrashekar, C. M.} } @article { WOS:000674685900001, title = {Quantum Computer Systems for Scientific Discovery}, journal = {PRX Quantum}, volume = {2}, number = {1}, year = {2021}, month = {FEB 24}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {The great promise of quantum computers comes with the dual challenges of building them and finding their useful applications. We argue that these two challenges should be considered together, by codesigning full-stack quantum computer systems along with their applications in order to hasten their development and potential for scientific discovery. In this context, we identify scientific and community needs, opportunities, a sampling of a few use case studies, and significant challenges for the development of quantum computers for science over the next 2-10 years. This document is written by a community of university, national laboratory, and industrial researchers in the field of Quantum Information Science and Technology, and is based on a summary from a U.S. National Science Foundation workshop on Quantum Computing held on October 21-22, 2019 in Alexandria, VA.}, doi = {10.1103/PRXQuantum.2.017001}, author = {Alexeev, Yuri and Bacon, Dave and Brown, Kenneth R. and Calderbank, Robert and Carr, Lincoln D. and Chong, Frederic T. and DeMarco, Brian and Englund, Dirk and Farhi, Edward and Fefferman, Bill and Gorshkov, V, Alexey and Houck, Andrew and Kim, Jungsang and Kimmel, Shelby and Lange, Michael and Lloyd, Seth and Lukin, Mikhail D. and Maslov, Dmitri and Maunz, Peter and Monroe, Christopher and Preskill, John and Roetteler, Martin and Savage, Martin J. and Thompson, Jeff} } @article {austin_quantum_2021, title = {Quantum critical dynamics in a spinor {Hubbard} model quantum simulator}, journal = {Commun. Phys.}, volume = {4}, number = {1}, year = {2021}, note = {Place: HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY Publisher: NATURE RESEARCH Type: Article}, month = {mar}, abstract = {Three-dimensional (3D) strongly correlated many-body systems, especially their dynamics across quantum phase transitions, are prohibitively difficult to be numerically simulated. We experimentally demonstrate that such complex many-body dynamics can be efficiently studied in a 3D spinor Bose-Hubbard model quantum simulator, consisting of antiferromagnetic spinor Bose-Einstein condensates confined in cubic optical lattices. We find dynamics and scaling effects beyond the scope of existing theories at superfluid-insulator quantum phase transitions, and highlight spin populations as a good observable to probe the quantum critical dynamics. Our data indicate that the scaling exponents are independent of the nature of the quantum phase transitions. We also conduct numerical simulations in lower dimensions using time-dependent Gutzwiller approximations, which qualitatively describe our observations. Three-dimensional (3D) strongly correlated many-body systems and their dynamics across quantum phase transitions pose a challenge when it comes to numerical simulations. The authors experimentally demonstrated that such many-body dynamics can be efficiently studied in a 3D spinor Bose-Hubbard model quantum simulator, and observed dynamics and scaling effects beyond the scope of existing theories at superfluid-insulator quantum phase transitions.}, issn = {2399-3650}, doi = {10.1038/s42005-021-00562-y}, author = {Austin, Jared O. and Chen, Zihe and Shaw, Zachary N. and Mahmud, Khan W. and Liu, Yingmei} } @article { WOS:000643598200024, title = {Quantum Matched Filtering-Signal Processing in the Quantum Age}, journal = {Johns Hopkins APL Tech. Dig.}, volume = {35}, number = {4}, year = {2021}, pages = {422-425}, publisher = {JOHNS HOPKINS UNIV APPLIED PHYSICS LABORATORY LLC}, type = {Article}, abstract = {Optimal quantum control theory identifies the quantum equivalent of a matched filter, which maximizes the signal-to-noise ratio, enabling exploitation of extremely high sensitivity of quantum sensors to detect known signals of interest. This article describes a Johns Hopkins University Applied Physics Laboratory (APL) team{\textquoteright}s work in this field.}, issn = {0270-5214}, author = {Titum, Paraj and Schultz, Kevin M. and Seif, Alireza and Quiroz, Gregory D. and Clader, B. David} } @article { WOS:000691579200002, title = {Quantum routing with fast reversals}, journal = {Quantum}, volume = {5}, year = {2021}, month = {AUG 31}, publisher = {VEREIN FORDERUNG OPEN ACCESS PUBLIZIERENS QUANTENWISSENSCHAF}, type = {Article}, abstract = {We present methods for implementing arbitrary permutations of qubits under interaction constraints. Our protocols make use of previous methods for rapidly reversing the order of qubits along a path. Given nearest-neighbor interactions on a path of length n, we show that there exists a constant epsilon approximate to 0.034 such that the quantum routing time is at most (1 - epsilon)n, whereas any SWAP-based protocol needs at least time n - 1. This represents the first known quantum advantage over SWAP-based routing methods and also gives improved quantum routing times for realistic architectures such as grids. Furthermore, we show that our algorithm approaches a quantum routing time of 2n/3 in expectation for uniformly random permutations, whereas SWAP-based protocols require time n asymptotically. Additionally, we consider sparse permutations that route k <= n qubits and give algorithms with quantum routing time at most n/3 + O(k(2)) on paths and at most 2r/3 + O(k(2)) on general graphs with radius r.}, issn = {2521-327X}, author = {Bapat, Aniruddha and Childs, Andrew M. and V. Gorshkov, Alexey and King, Samuel and Schoute, Eddie and Shastri, Hrishee} } @article { WOS:000674685900003, title = {Quantum Simulators: Architectures and Opportunities}, journal = {PRX Quantum}, volume = {2}, number = {1}, year = {2021}, month = {FEB 24}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Quantum simulators are a promising technology on the spectrum of quantum devices from specialized quantum experiments to universal quantum computers. These quantum devices utilize entanglement and many-particle behavior to explore and solve hard scientific, engineering, and computational problems. Rapid development over the last two decades has produced more than 300 quantum simulators in operation worldwide using a wide variety of experimental platforms. Recent advances in several physical architectures promise a golden age of quantum simulators ranging from highly optimized special purpose simulators to flexible programmable devices. These developments have enabled a convergence of ideas drawn from fundamental physics, computer science, and device engineering. They have strong potential to address problems of societal importance, ranging from understanding vital chemical processes, to enabling the design of new materials with enhanced performance, to solving complex computational problems. It is the position of the community, as represented by participants of the National Science Foundation workshop on {\textquoteleft}{\textquoteleft}Programmable Quantum Simulators,{{\textquoteright}{\textquoteright}} that investment in a national quantum simulator program is a high priority in order to accelerate the progress in this field and to result in the first practical applications of quantum machines. Such a program should address two areas of emphasis: (1) support for creating quantum simulator prototypes usable by the broader scientific community, complementary to the present universal quantum computer effort in industry; and (2) support for fundamental research carried out by a blend of multi-investigator, multidisciplinary collaborations with resources for quantum simulator software, hardware, and education. This document is a summary from a U.S. National Science Foundation supported workshop held on 16-17 September 2019 in Alexandria, VA. Attendees were charged to identify the scientific and community needs, opportunities, and significant challenges for quantum simulators over the next 2-5 years.}, doi = {10.1103/PRXQuantum.2.017003}, author = {Altman, Ehud and Brown, Kenneth R. and Carleo, Giuseppe and Carr, Lincoln D. and Demler, Eugene and Chin, Cheng and DeMarco, Brian and Economou, Sophia E. and Eriksson, Mark A. and Fu, Kai-Mei C. and Greiner, Markus and Hazzard, Kaden R. A. and Hulet, Randall G. and Kollar, Alicia J. and Lev, Benjamin L. and Lukin, Mikhail D. and Ma, Ruichao and Mi, Xiao and Misra, Shashank and Monroe, Christopher and Murch, Kater and Nazario, Zaira and Ni, Kang-Kuen and Potter, Andrew C. and Roushan, Pedram and Saffman, Mark and Schleier-Smith, Monika and Siddiqi, Irfan and Simmonds, Raymond and Singh, Meenakshi and Spielman, I. B. and Temme, Kristan and Weiss, David S. and Vuckovic, Jelena and Vuletic, Vladan and Ye, Jun and Zwierlein, Martin} } @article { WOS:000655928700001, title = {Quench Dynamics of a Fermi Gas with Strong Nonlocal Interactions}, journal = {Phys. Rev. X}, volume = {11}, number = {2}, year = {2021}, month = {MAY 17}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We induce strong nonlocal interactions in a 2D Fermi gas in an optical lattice using Rydberg dressing. The system is approximately described by a t - V model on a square lattice where the fermions experience isotropic nearest-neighbor interactions and are free to hop only along one direction. We measure the interactions using many-body Ramsey interferometry and study the lifetime of the gas in the presence of tunneling, finding that tunneling does not reduce the lifetime. To probe the interplay of nonlocal interactions with tunneling, we investigate the short-time-relaxation dynamics of charge-density waves in the gas. We find that strong nearest-neighbor interactions slow down the relaxation. Our work opens the door for quantum simulations of systems with strong nonlocal interactions such as extended Fermi-Hubbard models.}, issn = {2160-3308}, doi = {10.1103/PhysRevX.11.021036}, author = {Guardado-Sanchez, Elmer and Spar, Benjamin M. and Schauss, Peter and Belyansky, Ron and Young, Jeremy T. and Bienias, Przemyslaw and Gorshkov, V, Alexey and Iadecola, Thomas and Bakr, Waseem S.} } @article { WOS:000694043500003, title = {Reentrant Bloch ferromagnetism}, journal = {Phys. Rev. B}, volume = {104}, number = {10}, year = {2021}, month = {SEP 8}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {An interacting electron liquid in two (2D) and three (3D) dimensions may undergo a paramagnetic-to-ferromagnetic quantum spin polarization transition at zero applied magnetic field, driven entirely by exchange interactions, as the system density (n) is decreased. This is known as Bloch ferromagnetism. We show theoretically that the application of an external magnetic field (B), which directly spin polarizes the system through Zeeman spin splitting, has an interesting effect on Bloch ferromagnetism if the applied field and carrier density are both decreased (from some initial applied high magnetic field at a high carrier density) in a power-law manner, B similar to n(p). For pp(c), the system may undergo two transitions if starting from the fully spin-polarized state: first, a weak second-order transition at high density and field from the field-induced fully polarized phase to the partially polarized phase; and then, at a lower field and density, a reentrant first-order transition back to the fully spin-polarized phase again with a single Fermi surface.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.104.L100405}, author = {DinhDuy Vu and Das Sarma, S.} } @article { WOS:000664440600010, title = {Reply to "Comment on {\textquoteright}Nonequilibrium steady state phases of the interacting Aubry-Andre-Harper model{\textquoteright}"}, journal = {Phys. Rev. B}, volume = {103}, number = {23}, year = {2021}, month = {JUN 21}, publisher = {AMER PHYSICAL SOC}, type = {Editorial Material}, issn = {2469-9950}, doi = {10.1103/PhysRevB.103.237102}, author = {Yoo, Yongchan and Lee, Junhyun and Swingle, Brian} } @article {poniatowski_resistivity_2021, title = {Resistivity saturation in an electron-doped cuprate}, journal = {Phys. Rev. B}, volume = {103}, number = {2}, year = {2021}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {jan}, abstract = {We report the observation of resistivity saturation in lightly doped (x = 0.08) as-grown samples of the electron-doped cuprate La2-xCexCuO4. The saturation occurs at resistivity values roughly consistent with the phenomenological Mott-Ioffe-Regel criterion once the low effective carrier density of these materials is included in the analysis. These results imply that, at least for light doping, the high-temperature metallic phase of these materials is not necessarily strange and may be understood as simply a low-density metal.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.103.L020501}, author = {Poniatowski, Nicholas R. and Sarkar, Tarapada and Das Sarma, Sankar and Greene, Richard L.} } @article { WOS:000647126400002, title = {Screening, Friedel oscillations, RKKY interaction, and Drude transport in anisotropic two-dimensional systems}, journal = {Phys. Rev. B}, volume = {103}, number = {16}, year = {2021}, month = {APR 7}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We investigate the effect of the mass anisotropy on Friedel oscillations, Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction, screening properties, and Boltzmann transport in two-dimensional (2D) metallic and doped semiconductor systems. We calculate the static polarizability and the dielectric function within the random phase approximation with the mass anisotropy fully taken into account without making any effective isotropic approximation in the theory. We find that carrier screening exhibits an isotropic behavior for small momenta despite the anisotropy of the system and becomes strongly anisotropic above a certain threshold momentum. Such an anisotropy of screening leads to anisotropic Friedel oscillations, and an anisotropic RKKY interaction characterized by a periodicity dependent on the direction between the localized magnetic moments. We also explore the disorder limited dc transport properties in the presence of mass anisotropy based on the Boltzmann transport theory. Interestingly, we find that the anisotropy ratio of the short-range disorder limited resistivity along the heavy- and light-mass directions is always the same as the mass anisotropy ratio, whereas for the long-range disorder limited resistivity the anisotropy ratio is the same as the mass ratio only in the low-density limit and saturates to the square root of the mass ratio in the high-density limit. Our theoretical work should apply to many existing and to-be-discovered anisotropic 2D systems.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.103.165303}, author = {Ahn, Seongjin and Das Sarma, S.} } @article { WOS:000714581000004, title = {Self-Bayesian aberration removal via constraints for ultracold atom microscopy}, journal = {Phys. Rev. Res.}, volume = {3}, number = {4}, year = {2021}, month = {OCT 29}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {High-resolution imaging of ultracold atoms typically requires custom high numerical aperture (NA) optics, as is the case for quantum gas microscopy. These high NA objectives involve many optical elements, each of which contributes to loss and light scattering, making them unsuitable for quantum backaction limited {\textquoteleft}{\textquoteleft}weak{{\textquoteright}{\textquoteright}} measurements. We employ a low-cost high NA aspheric lens as an objective for a practical and economical-although aberrated-high-resolution microscope to image Rb-87 Bose-Einstein condensates. Here, we present a methodology for digitally eliminating the resulting aberrations that is applicable to a wide range of imaging strategies and requires no additional hardware. We recover nearly the full NA of our objective, thereby demonstrating a simple and powerful digital aberration correction method for achieving optimal microscopy of quantum objects. This reconstruction relies on a high-quality measure of our imaging system{\textquoteright}s even-order aberrations from density-density correlations measured with differing degrees of defocus. We demonstrate our aberration compensation technique using phase-contrast imaging, a dispersive imaging technique directly applicable to quantum backaction limited measurements. Furthermore, we show that our digital correction technique reduces the contribution of photon shot noise to density-density correlation measurements which would otherwise contaminate the desired quantum projection noise signal in weak measurements.}, doi = {10.1103/PhysRevResearch.3.043087}, author = {Altuntas, Emine and Spielman, I. B.} } @article { WOS:000704295900053, title = {Single-Molecule Measurements Spatially Probe States Involved in Electron Transfer from CdSe/CdS Core/Shell Nanorods}, journal = {J. Phys. Chem. C}, volume = {125}, number = {38, SI}, year = {2021}, month = {SEP 30}, pages = {21246-21253}, publisher = {AMER CHEMICAL SOC}, type = {Article}, abstract = {Semiconductor nanorods with charge-accepting molecules adsorbed on their surfaces serve as model systems for solar energy conversion. An electron photoexcited from the valence band of the nanorod to a high-energy state in the conduction band will relax and transfer to a state in the molecule, producing a long-lived charge-separated state that facilitates charge extraction and thereby enables photochemical reactions. Characterizing the dynamics of the charge-separation process and the electronic states involved is essential for a microscopic understanding of photocatalysis involving these materials, but this information is obscured in ensemble measurements due to the random placement of molecules on the nanorod surfaces. Here, we show that measurements on individual CdSe/CdS core/shell nanorods functionalized by single methyl viologen molecules provide information about the distribution of electron-transfer rates from confined states in the nanorods to states in the molecules. By comparing this transfer-rate distribution to the predictions of a tight-binding model, we find that charge transfer most likely involves hot electrons in an excited conduction-band state, rather than electrons that have fully thermalized to the conduction-band edge. The ability to extract hot electrons from semiconductor nanocrystals may help enable energy-efficient photocatalysis, and the single-particle charge-transfer method may serve as a widely applicable tool to probe the spatial distribution of electronic states in nanocrystals.}, issn = {1932-7447}, doi = {10.1021/acs.jpcc.1c06581}, author = {Morin, Rachel M. and Bryant, Garnett W. and Shevchenko, V, Elena and Sha, Yuchen and Pelton, Matthew} } @article { WOS:000736648600001, title = {Spin-Valley Qubit Dynamics in Exchange-Coupled Silicon Quantum Dots}, journal = {PRX Quantum}, volume = {2}, number = {4}, year = {2021}, month = {DEC 23}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {The presence of valley states is a significant obstacle to realizing quantum information technologies in silicon quantum dots, as leakage into alternate valley states can introduce errors into the computation. We use a perturbative analytical approach to study the dynamics of exchange-coupled quantum dots with valley degrees of freedom. We show that if the valley splitting is large and electrons are not properly initialized to valley eigenstates, then the time evolution of the system will lead to spin-valley entanglement. Spin-valley entanglement will also occur if the valley splitting is small and electrons are not initialized to the same valley state. Additionally, we show that for small valley splitting, spin-valley entanglement does not affect the measurement probabilities of two-qubit systems; however, systems with more qubits will be affected. This means that two-qubit gate fidelities measured in two-qubit systems may miss the effects of valley degrees of freedom. Our work shows how the existence of valleys may adversely affect multiqubit fidelities even when the system temperature is very low. Although this is not an immediate problem in Si qubits, because the current focus is on controlling individual qubits, our work points to a possible future issue in many-qubit Si circuits.}, doi = {10.1103/PRXQuantum.2.040358}, author = {Buterakos, Donovan and Das Sarma, Sankar} } @article { WOS:000645519800001, title = {Spontaneous pulse formation in edgeless photonic crystal resonators}, journal = {Nat. Photonics}, volume = {15}, number = {6}, year = {2021}, month = {JUN}, pages = {461+}, publisher = {NATURE RESEARCH}, type = {Article}, abstract = {Nonlinearity in complex systems leads to pattern formation through fundamental interactions between components. With integrated photonics, precision control of nonlinearity explores novel patterns and propels applications. In particular, Kerr-nonlinear resonators support stationary states-including Turing patterns-composed of a few interfering waves, and localized solitons composed of waves across a broad spectrum. Although Turing patterns emerge from an unstable Kerr resonator with sufficiently intense excitation, Kerr solitons do not form spontaneously under constant excitation, making this useful state challenging to access. Here we explore an edgeless photonic crystal resonator (PhCR) that enables spontaneous soliton formation in place of Turing patterns. We design the PhCR nanopattern for single-azimuthal-mode engineering of a group-velocity-dispersion defect that balances Kerr-nonlinear frequency shifts in favour of the soliton state. Our experiments establish PhCR solitons as modelocked pulses through ultraprecise optical-frequency measurements. We show that nanophotonics expand the palette for nonlinear engineering, enabling new phenomena and light sources. Researchers have demonstrated spontaneous soliton formation in an edgeless photonic crystal resonator.}, issn = {1749-4885}, doi = {10.1038/s41566-021-00800-3}, author = {Yu, Su-Peng and Cole, Daniel C. and Jung, Hojoong and Moille, Gregory T. and Srinivasan, Kartik and Papp, Scott B.} } @article { WOS:000647175700003, title = {Studying many-body localization in exchange-coupled electron spin qubits using spin-spin correlations}, journal = {Phys. Rev. B}, volume = {103}, number = {16}, year = {2021}, month = {APR 29}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We show that many-body localization (MBL) effects can be observed in a finite chain of exchange-coupled spin qubits in the presence of both exchange and magnetic noise, a system that has been experimentally realized in semiconductors and is a potential solid-state quantum computing platform. In addition to established measures of MBL, the level spacing ratio and the entanglement entropy, we propose another quantity, the spin-spin correlation function, that can be measured experimentally and is particularly well-suited to experiments in semiconductor-based electron spin qubit systems. We show that, in cases that the established measures detect as delocalized {\textquoteleft}{\textquoteleft}phases,{{\textquoteright}{\textquoteright}} the spin-spin correlation functions retain no memory of the system{\textquoteright}s initial state (i.e., the long-time value deviates significantly from the initial value), but that they do retain memory in cases that the established measures detect as localized {\textquoteleft}{\textquoteleft}phases.{{\textquoteright}{\textquoteright}} We also discover an interesting counterintuitive result that there is no clear tendency towards localization with increasing charge noise in small systems (3-10 spins). The proposed experiments should be feasible in the existing semiconductor spin qubit systems.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.103.165431}, author = {Throckmorton, Robert E. and Das Sarma, S.} } @article {shivam_studying_2021, title = {Studying {Viral} {Populations} with {Tools} from {Quantum} {Spin} {Chains}}, journal = {J. Stat. Phys.}, volume = {182}, number = {2}, year = {2021}, note = {Place: ONE NEW YORK PLAZA, SUITE 4600, NEW YORK, NY, UNITED STATES Publisher: SPRINGER Type: Article}, month = {feb}, abstract = {

We study Eigen{\textquoteright}s model of quasi-species (Eigen in Selforganization of matter and the evolution of biological macromolecules. Naturwissenschaften 58(10):465, 1971), characterized by sequences that replicate with a specified fitness and mutate independently at single sites. The evolution of the population vector in time is then closely related to that of quantum spins in imaginary time. We employ multiple perspectives and tools from interacting quantum systems to examine growth and collapse of realistic viral populations, specifically considering excessive mutations in certain HIV proteins. All approaches used, including the simplest perturbation theory, give consistent results.

}, keywords = {Biological evolution, HIV, Quantum spin chains}, issn = {0022-4715}, doi = {10.1007/s10955-021-02716-2}, author = {Shivam, Saumya and Baldwin, Christopher L. and Barton, John and Kardar, Mehran and Sondhi, S. L.} } @article { WOS:000707469900008, title = {Superconductors with anomalous Floquet higher-order topology}, journal = {Phys. Rev. B}, volume = {104}, number = {14}, year = {2021}, month = {OCT 11}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We develop a general theory for two-dimensional (2D) anomalous Floquet higher-order topological superconductors (AFHOTSCs), which are dynamical Majorana-carrying phases of matter with no static counterpart. Despite the triviality of its bulk Floquet bands, an AFHOTSC generically features the simultaneous presence of corner-localized Majorana modes at both zero and pi/T quasienergies, a phenomenon beyond the scope of any static topological band theory. We show that the key to AFHOTSCs is their unavoidable singular behavior in the phase spectrum of the bulk time-evolution operator. By mapping such evolution-phase singularities to the stroboscopic boundary signatures, we classify 2D AFHOTSCs that are protected by a rotation group symmetry in symmetry class D. We further extract a higher-order topological index for unambiguously predicting the presence of Floquet corner Majorana modes, which we confirm numerically. Our theory serves as a milestone towards a dynamical topological theory for Floquet superconducting systems.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.104.L140502}, author = {Vu, DinhDuy and Zhang, Rui-Xing and Yang, Zhi-Cheng and Das Sarma, S.} } @article { WOS:000704414100002, title = {Symmetry-breaking signatures of multiple Majorana zero modes in one-dimensional spin-triplet superconductors}, journal = {Phys. Rev. B}, volume = {104}, number = {10}, year = {2021}, month = {SEP 28}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We study the effects of various symmetry-breaking perturbations on the experimentally measurable signatures (such as conductance and Josephson response) of quasi-one-dimensional (quasi-1D) spin-triplet superconductors. In the first part of the paper, we numerically compute the zero and nonzero temperature conductances of the quasi-1D nanowires that host multiple Majorana zero modes. Following the discussion of the case of s-wave Rashba nanowires, we shift to the main focus, i.e., multi-channel spin-triplet superconductors. Applying gate voltages (which changes the symmetry of the spin-orbit coupling) as well as magnetic fields to the nanowire, tunes the system between different symmetry classes by splitting the multiple Majorana zero modes. We study how the conductance tracks the topological invariants and the spectra in all these cases. In the second part of the paper, we study the effects of the symmetry-induced spectrum-breaking on the Andreev spectra of Josephson junctions Similar to the case of the conductance studies, we find that the spectrum shows multiple zero-energy Andreev bound states in the highly symmetric case with mirror and chiral symmetries.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.104.104513}, author = {Ray, Arnab Barman and Sau, Jay D. and Mandal, Ipsita} } @article { WOS:000724242500007, title = {Tailoring broadband Kerr soliton microcombs via post-fabrication tuning of the geometric dispersion}, journal = {Appl. Phys. Lett.}, volume = {119}, number = {12}, year = {2021}, month = {SEP 20}, publisher = {AIP Publishing}, type = {Article}, abstract = {Geometric dispersion in integrated microresonators plays a major role in nonlinear optics applications, especially at short wavelengths, to compensate the natural material normal dispersion. Tailoring of geometric confinement allows for anomalous dispersion, which, in particular, enables the formation of microcombs that can be tuned into the dissipative Kerr soliton (DKS) regime. Due to processes like soliton-induced dispersive wave generation, broadband DKS combs are particularly sensitive to higher-order dispersion, which, in turn, is sensitive to the ring dimensions at the nanometer-level. For microrings exhibiting a rectangular cross section, the ring width and thickness are the two main control parameters to achieve the targeted dispersion. The former can be easily varied through parameter variation within the lithography mask, yet the latter is defined by the film thickness during growth of the starting material stack and can show a significant variation (few percent of the total thickness) over a single wafer. In this Letter, we demonstrate that controlled dry-etching allows for fine tuning of the device layer (silicon nitride) thickness at the wafer level, allowing multi-project wafers targeting different wavelength bands and post-fabrication trimming in air-clad ring devices. We demonstrate that such dry etching does not significantly affect either the silicon nitride surface roughness or the optical quality of the devices, thereby enabling fine tuning of the dispersion and the spectral shape of the resulting DKS states. (C) 2021 Author(s).}, issn = {0003-6951}, doi = {10.1063/5.0061238}, author = {Moille, Gregory and Westly, Daron and Orji, Ndubuisi George and Srinivasan, Kartik} } @article { WOS:000646317500004, title = {Temperature-dependent energy diffusion in chaotic spin chains}, journal = {Phys. Rev. B}, volume = {103}, number = {11}, year = {2021}, month = {MAR 25}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We study the temperature dependence of energy diffusion in two chaotic gapped quantum spin chains, a tilted-field Ising model and an XZ model, using an open-system approach. We introduce an energy imbalance by coupling the chain to thermal baths at its boundary and study the nonequilibrium steady states of the resulting Lindblad dynamics using a matrix product operator ansatz for the density matrix. We define an effective local temperature profile by comparing local reduced density matrices in the steady state with those of a uniform thermal state. We then measure the energy current for a variety of driving temperatures and extract the temperature dependence of the energy diffusion constant. For the Ising model, we are able to study temperatures well below the energy gap and find a regime of dilute excitations where rare three-body collisions control energy diffusion. A kinetic model correctly predicts the observed exponential increase of the energy diffusion constant at low temperatures. For the XZ model, we are only able to access intermediate to high temperatures relative to the energy gap, and we show that the data are well described by an expansion around the infinite temperature limit. We also discuss the limitations of the particular driving scheme and suggest that lower temperatures can be accessed using larger baths.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.103.115148}, author = {Zanoci, Cristian and Swingle, Brian} } @article { WOS:000681124600002, title = {Theory of Coulomb blockaded transport in realistic Majorana nanowires}, journal = {Phys. Rev. B}, volume = {104}, number = {8}, year = {2021}, month = {AUG 3}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Coulomb blockaded transport of topological superconducting nanowires provides an opportunity to probe the localization of states at both ends of the system in a two-terminal geometry. In addition, it provides a way for checking for subgap states away from the leads. At the same time, Coulomb blockade transport is difficult to analyze because of the interacting nature of the problem arising from the nonperturbative Coulomb interaction inherent in the phenomenon. Here we show that the Coulomb blockade transport can be modeled at the same level of complexity as quantum point contact tunneling that has routinely been used in mesoscopic physics to understand nanowire experiments provided we consider the regime where the tunneling rate is below the equilibration rate of the nanowire. This assumption leads us to a generalized Meir-Wingreen formula for the tunnel conductance which we use to study various features of the nanowire such as Andreev bound states, self-energy, and soft gap. We anticipate that our theory will provide a route to interpret Coulomb blockade transport in hybrid Majorana systems as resulting from features of the nanowire, such as Andreev bound states and soft gaps.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.104.085403}, author = {Lai, Yi-Hua and Das Sarma, Sankar and Sau, Jay D.} } @article {childs_theory_2021, title = {Theory of {Trotter} {Error} with {Commutator} {Scaling}}, journal = {Phys. Rev. X}, volume = {11}, number = {1}, year = {2021}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {feb}, abstract = {The Lie-Trotter formula, together with its higher-order generalizations, provides a direct approach to decomposing the exponential of a sum of operators. Despite significant effort, the error scaling of such product formulas remains poorly understood. We develop a theory of Trotter error that overcomes the limitations of prior approaches based on truncating the Baker-Campbell-Hausdorff expansion. Our analysis directly exploits the commutativity of operator summands, producing tighter error bounds for both real- and imaginary-time evolutions. Whereas previous work achieves similar goals for systems with geometric locality or Lie-algebraic structure, our approach holds, in general. We give a host of improved algorithms for digital quantum simulation and quantum Monte Carlo methods, including simulations of second-quantized plane-wave electronic structure, k-local Hamiltonians, rapidly decaying power-law interactions, clustered Hamiltonians, the transverse field Ising model, and quantum ferromagnets, nearly matching or even outperforming the best previous results. We obtain further speedups using the fact that product formulas can preserve the locality of the simulated system. Specifically, we show that local observables can be simulated with complexity independent of the system size for power-law interacting systems, which implies a Lieb-Robinson bound as a by-product. Our analysis reproduces known tight bounds for first- and second-order formulas. Our higher-order bound overestimates the complexity of simulating a one-dimensional Heisenberg model with an even-odd ordering of terms by only a factor of 5, and it is close to tight for power-law interactions and other orderings of terms. This result suggests that our theory can accurately characterize Trotter error in terms of both asymptotic scaling and constant prefactor.

}, issn = {2160-3308}, doi = {10.1103/PhysRevX.11.011020}, author = {Childs, Andrew M. and Su, Yuan and Tran, Minh C. and Wiebe, Nathan and Zhu, Shuchen} } @article {pan_three-terminal_2021, title = {Three-terminal nonlocal conductance in {Majorana} nanowires: {Distinguishing} topological and trivial in realistic systems with disorder and inhomogeneous potential}, journal = {Phys. Rev. B}, volume = {103}, number = {1}, year = {2021}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {jan}, abstract = {We develop a theory for the three-terminal nonlocal conductance in Majorana nanowires as existing in the superconductor-semiconductor hybrid structures in the presence of superconducting proximity, spin-orbit coupling, and Zeeman splitting. The key question addressed is whether such nonlocal conductance can decisively distinguish between trivial and topological Majorana scenarios in the presence of chemical potential inhomogeneity and random impurity disorder. We calculate the local electrical as well as nonlocal electrical and thermal conductance of the pristine nanowire (good zero-bias conductance peaks), the nanowire in the presence of quantum dots and inhomogeneous potential (bad zero-bias conductance peaks), and the nanowire in the presence of large disorder (ugly zero-bias conductance peaks). The local conductance by itself is incapable of distinguishing the trivial states from the topological states since zero-bias conductance peaks are generic in the presence of disorder and inhomogeneous potential. The nonlocal conductance, which in principle is capable of providing the bulk gap closing and reopening information at the topological quantum phase transition, is found to be far too weak in magnitude to be particularly useful in the presence of disorder and inhomogeneous potential. Therefore, we focus on the question of whether the combination of the local, nonlocal electrical, and thermal conductance can separate the good, bad, and ugly zero-bias conductance peaks in finite-length wires. Our paper aims to provide a guide to future experiments, and we conclude that a combination of all three measurements would be necessary for a decisive demonstration of topological Majorana zero modes in nanowires-positive signals corresponding to just one kind of measurements are likely to be false positives arising from disorder and inhomogeneous potential.

}, issn = {2469-9950}, doi = {10.1103/PhysRevB.103.014513}, author = {Pan, Haining and Sau, Jay D. and Sankar Das Sarma} } @article { WOS:000655930100005, title = {Topological Defect Engineering and PT Symmetry in Non-Hermitian Electrical Circuits}, journal = {Phys. Rev. Lett.}, volume = {126}, number = {21}, year = {2021}, month = {MAY 28}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We employ electric circuit networks to study topological states of matter in non-Hermitian systems enriched by parity-time symmetry PT and chiral symmetry anti-PT (APT). The topological structure manifests itself in the complex admittance bands which yields excellent measurability and signal to noise ratio. We analyze the impact of PT-symmetric gain and loss on localized edge and defect states in a non-Hermitian Su-Schrieffer-Heeger (SSH) circuit. We realize all three symmetry phases of the system, including the APT-symmetric regime that occurs at large gain and loss. We measure the admittance spectrum and eigenstates for arbitrary boundary conditions, which allows us to resolve not only topological edge states, but also a novel PT-symmetric Z(2) invariant of the bulk. We discover the distinct properties of topological edge states and defect states in the phase diagram. In the regime that is not PT symmetric, the topological defect state disappears and only reemerges when APT symmetry is reached, while the topological edge states always prevail and only experience a shift in eigenvalue. Our findings unveil a future route for topological defect engineering and tuning in non-Hermitian systems of arbitrary dimension.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.126.215302}, author = {Stegmaier, Alexander and Imhof, Stefan and Helbig, Tobias and Hoefmann, Tobias and Lee, Ching Hua and Kremer, Mark and Fritzsche, Alexander and Feichtner, Thorsten and Klembt, Sebastian and Hofling, Sven and Boettcher, Igor and Fulga, Ion Cosma and Ma, Libo and Schmidt, Oliver G. and Greiter, Martin and Kiessling, Tobias and Szameit, Alexander and Thomale, Ronny} } @article {19181, title = {Topological features without a lattice in Rashba spin-orbit coupled atoms}, journal = {Nature Communications}, volume = {12}, year = {2021}, month = {01/2021}, abstract = {Topological order can be found in a wide range of physical systems, from crystalline solids, photonic meta-materials and even atmospheric waves to optomechanic, acoustic and atomic systems. Topological systems are a robust foundation for creating quantized channels for transporting electrical current, light, and atmospheric disturbances. These topological effects are quantified in terms of integer-valued {\textquoteleft}invariants{\textquoteright}, such as the Chern number, applicable to the quantum Hall effect, or the\ Z2Z2\ invariant suitable for topological insulators. Here, we report the engineering of Rashba spin-orbit coupling for a cold atomic gas giving non-trivial topology, without the underlying crystalline structure that conventionally yields integer Chern numbers. We validated our procedure by spectroscopically measuring both branches of the Rashba dispersion relation which touch at a single Dirac point. We then measured the quantum geometry underlying the dispersion relation using matter-wave interferometry to implement a form of quantum state tomography, giving a Berry{\textquoteright}s phase with magnitude\ *Ï€*. This implies that opening a gap at the Dirac point would give two dispersions (bands) each with half-integer Chern number, potentially implying new forms of topological transport.

Recent advances in realizing optical frequency combs using nonlinear parametric processes in integrated photonic resonators have revolutionized on-chip optical clocks, spectroscopy and multichannel optical communications. At the same time, the introduction of topological physics in photonic systems has allowed the design of photonic devices with novel functionalities and inherent robustness against fabrication disorders. Here we use topological design principles to theoretically propose the generation of optical frequency combs and temporal dissipative Kerr solitons in a two-dimensional array of coupled ring resonators that creates a synthetic magnetic field for photons and exhibits topological edge states. We show that these topological edge states constitute a travelling-wave super-ring resonator that leads to the generation of coherent nested optical frequency combs, as well as the self-formation of nested temporal solitons and Turing rolls that are remarkably phase-locked over more than 40 rings. Moreover, we show that the topological nested solitons are robust against defects in the lattice, and a single nested soliton achieves a mode efficiency of over 50{\%}, an order of magnitude higher than single-ring frequency combs. Our topological frequency comb works in a parameter regime that can be readily accessed using existing low-loss integrated photonic platforms like silicon nitride.

}, isbn = {1745-2481}, doi = {10.1038/s41567-021-01302-3}, url = {https://doi.org/10.1038/s41567-021-01302-3}, author = {Mittal, Sunil and Moille, Gregory and Srinivasan, Kartik and Chembo, Yanne K. and Hafezi, Mohammad} } @article { WOS:000646178000004, title = {Torus spectroscopy of the Gross-Neveu-Yukawa quantum field theory: Free Dirac versus chiral Ising fixed point}, journal = {Phys. Rev. B}, volume = {103}, number = {12}, year = {2021}, month = {MAR 12}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We establish the universal torus low-energy spectra at the free Dirac fixed point and at the strongly coupled chiral Ising fixed point and their subtle crossover behavior in the Gross-Neuveu-Yukawa field theory with n(D) = 4 component Dirac spinors in D = (2 + 1) dimensions. These fixed points and the field theories are directly relevant for the long-wavelength physics of certain interacting Dirac systems, such as repulsive spinless fermions on the honeycomb lattice or pi-flux square lattice. The torus energy spectrum has been shown previously to serve as a characteristic fingerprint of relativistic fixed points and is a powerful tool to discriminate quantum critical behavior in numerical simulations. Here, we use a combination of exact diagonalization and quantum Monte Carlo simulations of strongly interacting fermionic lattice models, to compute the critical torus energy spectrum on finite-size clusters with periodic boundaries and extrapolate them to the thermodynamic limit. Additionally, we compute the torus energy spectrum analytically using the perturbative expansion in epsilon = 4 - D, which is in good agreement with the numerical results, thereby validating the presence of the chiral Ising fixed point in the lattice models at hand. We show that the strong interaction between the spinor field and the scalar order-parameter field strongly influences the critical torus energy spectrum and we observe prominent multiplicity features related to an emergent symmetry predicted from the quantum field theory. Building on these results we are able to address the subtle crossover physics of the low-energy spectrum flowing from the chiral Ising fixed point to the Dirac fixed point, and analyze earlier flawed attempts to extract Fermi velocity renormalizations from the low-energy spectrum.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.103.125128}, author = {Schuler, Michael and Hesselmann, Stephan and Whitsitt, Seth and Lang, Thomas C. and Wessel, Stefan and Laeuchli, Andreas M.} } @article { WOS:000655094800001, title = {Towards integrated photonic interposers for processing octave-spanning microresonator frequency combs}, journal = {Light-Sci. Appl.}, volume = {10}, number = {1}, year = {2021}, month = {MAY 26}, publisher = {SPRINGERNATURE}, type = {Article}, abstract = {Microcombs-optical frequency combs generated in microresonators-have advanced tremendously in the past decade, and are advantageous for applications in frequency metrology, navigation, spectroscopy, telecommunications, and microwave photonics. Crucially, microcombs promise fully integrated miniaturized optical systems with unprecedented reductions in cost, size, weight, and power. However, the use of bulk free-space and fiber-optic components to process microcombs has restricted form factors to the table-top. Taking microcomb-based optical frequency synthesis around 1550 nm as our target application, here, we address this challenge by proposing an integrated photonics interposer architecture to replace discrete components by collecting, routing, and interfacing octave-wide microcomb-based optical signals between photonic chiplets and heterogeneously integrated devices. Experimentally, we confirm the requisite performance of the individual passive elements of the proposed interposer-octave-wide dichroics, multimode interferometers, and tunable ring filters, and implement the octave-spanning spectral filtering of a microcomb, central to the interposer, using silicon nitride photonics. Moreover, we show that the thick silicon nitride needed for bright dissipative Kerr soliton generation can be integrated with the comparatively thin silicon nitride interposer layer through octave-bandwidth adiabatic evanescent coupling, indicating a path towards future system-level consolidation. Finally, we numerically confirm the feasibility of operating the proposed interposer synthesizer as a fully assembled system. Our interposer architecture addresses the immediate need for on-chip microcomb processing to successfully miniaturize microcomb systems and can be readily adapted to other metrology-grade applications based on optical atomic clocks and high-precision navigation and spectroscopy.}, issn = {2047-7538}, doi = {10.1038/s41377-021-00549-y}, author = {Rao, Ashutosh and Moille, Gregory and Lu, Xiyuan and Westly, Daron A. and Sacchetto, Davide and Geiselmann, Michael and Zervas, Michael and Papp, Scott B. and Bowers, John and Srinivasan, Kartik} } @article { WOS:000654369300061, title = {Two-beam coupling in the production of quantum correlated images by four-wave mixing}, journal = {Opt. Express}, volume = {29}, number = {11}, year = {2021}, month = {MAY 24}, pages = {16665-16675}, publisher = {OPTICAL SOC AMER}, type = {Article}, abstract = {We investigate the effect of 2-beam coupling in different imaging geometries in generating intensity-difference squeezing from four-wave mixing (4WM) in Rb atomic vapors. A recently-introduced dual-seeding technique can cancel out the classical noise in a seeded four-wave mixing process. This dual-seeding technique, however, can introduce new complications that involve 2-beam coupling between different seeded spatial modes in the atomic vapor and can ruin squeezing at frequencies on the order of the atomic linewidth and below. This complicates some forms of quantum imaging using these systems. Here we show that seeding the 4WM process with skew rays can eliminate the excess noise caused by 2-beam coupling. To avoid 2-beam coupling in bright, seeded images, it is important to re-image the object in the gain medium, instead of focussing through it. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement}, issn = {1094-4087}, doi = {10.1364/OE.424392}, author = {Wu, Meng-Chang and Brewer, Nicholas R. and Speirs, Rory W. and Jones, Kevin M. and Lett, Paul D.} } @article { WOS:000730391400013, title = {Ultra-broadband Kerr microcomb through soliton spectral translation}, journal = {Nat. Commun.}, volume = {12}, number = {1}, year = {2021}, month = {DEC 14}, publisher = {NATURE PORTFOLIO}, type = {Article}, abstract = {Broadband and low-noise microresonator frequency combs (microcombs) are critical for deployable optical frequency measurements. Here we expand the bandwidth of a microcomb far beyond its anomalous dispersion region on both sides of its spectrum through spectral translation mediated by mixing of a dissipative Kerr soliton and a secondary pump. We introduce the concept of synthetic dispersion to qualitatively capture the system{\textquoteright}s key physical behavior, in which the second pump enables spectral translation through four-wave mixing Bragg scattering. Experimentally, we pump a silicon nitride microring at 1063 nm and 1557 nm to enable soliton spectral translation, resulting in a total bandwidth of 1.6 octaves (137-407 THz). We examine the comb{\textquoteright}s low-noise characteristics, through heterodyne beat note measurements across its spectrum, measurements of the comb tooth spacing in its primary and spectrally translated portions, and their relative noise. These ultra-broadband microcombs provide new opportunities for optical frequency synthesis, optical atomic clocks, and reaching previously unattainable wavelengths. Integrated optical frequency measurements, benefit from broadband on-chip frequency combs. Here the authors present a low-noise microcomb whose span extends from telecom to near-visible wavelengths. Here the authors present a dissipative Kerr soliton formation approximated by introducing the concept of synthetic dispersion.}, doi = {10.1038/s41467-021-27469-0}, author = {Moille, Gregory and Perez, Edgar F. and Stone, Jordan R. and Rao, Ashutosh and Lu, Xiyuan and Rahman, Tahmid Sami and Chembo, Yanne K. and Srinivasan, Kartik} } @article { WOS:000702389700001, title = {Wilson loop and Wilczek-Zee phase from a non-Abelian gauge field}, journal = {npj Quantum Inform.}, volume = {7}, number = {1}, year = {2021}, month = {SEP 30}, publisher = {NATURE PORTFOLIO}, type = {Article}, abstract = {Quantum states can acquire a geometric phase called the Berry phase after adiabatically traversing a closed loop, which depends on the path not the rate of motion. The Berry phase is analogous to the Aharonov-Bohm phase derived from the electromagnetic vector potential, and can be expressed in terms of an Abelian gauge potential called the Berry connection. Wilczek and Zee extended this concept to include non-Abelian phases-characterized by the gauge-independent Wilson loop-resulting from non-Abelian gauge potentials. Using an atomic Bose-Einstein condensate, we quantum-engineered a non-Abelian SU(2) gauge field, generated by a Yang monopole located at the origin of a 5-dimensional parameter space. By slowly encircling the monopole, we characterized the Wilczek-Zee phase in terms of the Wilson loop, that depended on the solid-angle subtended by the encircling path: a generalization of Stokes{\textquoteright} theorem. This observation marks the observation of the Wilson loop resulting from a non-Abelian point source.}, doi = {10.1038/s41534-021-00483-2}, author = {Sugawa, Seiji and Salces-Carcoba, Francisco and Yue, Yuchen and Putra, Andika and Spielman, I. B.} } @article { WOS:000688493300002, title = {Z(2) topological order and first-order quantum phase transitions in systems with combinatorial gauge symmetry}, journal = {Phys. Rev. B}, volume = {104}, number = {8}, year = {2021}, month = {AUG 24}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We study a generalization of the two-dimensional transverse-field Ising model, combining both ferromagnetic and antiferromagnetic two-body interactions, that hosts exact global and local Z(2) gauge symmetries. Using exact diagonalization and stochastic series expansion quantum Monte Carlo methods, we confirm the existence of the topological phase in line with previous theoretical predictions. Our simulation results show that the transition between the confined topological phase and the deconfined paramagnetic phase is of first order, in contrast to the conventional Z(2) lattice gauge model in which the transition maps onto that of the standard Ising model and is continuous. We further generalize the model by replacing the transverse field on the gauge spins with a ferromagnetic XX interaction while keeping the local gauge symmetry intact. We find that the Z(2) topological phase remains stable, while the paramagnetic phase is replaced by a ferromagnetic phase. The topological-ferromagnetic quantum phase transition is also of first order. For both models, we discuss the low-energy spinon and vison excitations of the topological phase and their avoided level crossings associated with the first-order quantum phase transitions.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.104.085145}, author = {Wu, Kai-Hsin and Yang, Zhi-Cheng and Green, Dmitry and Sandvik, Anders W. and Chamon, Claudio} } @article { ISI:000528518000008, title = {Accurate Prediction of Clock Transitions in a Highly Charged Ion with Complex Electronic Structure}, journal = {Phys. Rev. Lett.}, volume = {124}, number = {16}, year = {2020}, month = {APR 24}, pages = {163001}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We develop a broadly applicable approach that drastically increases the ability to predict the properties of complex atoms accurately. We apply it to the case of Ir-17(+), which is of particular interest for the development of novel atomic clocks with a high sensitivity to the variation of the fine-structure constant and to dark matter searches. In general, clock transitions are weak and very difficult to identify without accurate theoretical predictions. In the case of Ir-17(+), even stronger electric-dipole (El) transitions have eluded observation despite years of effort, raising the possibility that the theoretical predictions are grossly wrong. In this work, we provide accurate predictions of the transition wavelengths and E1 transition rates for Ir-17(+). Our results explain the lack of observations of the E1 transitions and provide a pathway toward the detection of clock transitions. The computational advances we demonstrate in this work are widely applicable to most elements in the periodic table and will allow us to solve numerous problems in atomic physics, astrophysics, and plasma physics.

}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.124.163001}, author = {Cheung, C. and Safronova, M. S. and Porsev, S. G. and Kozlov, M. G. and Tupitsyn, I. I. and Bondarev, I. A.} } @article { ISI:000533306300001, title = {Analysing quantized resistance behaviour in graphene Corbino p-n junction devices}, journal = {J. Phys. D-Appl. Phys.}, volume = {53}, number = {27}, year = {2020}, month = {JUL 1}, pages = {275301}, publisher = {IOP PUBLISHING LTD}, type = {Article}, abstract = {Just a few of the promising applications of graphene Corbino pnJ devices include two-dimensional Dirac fermion microscopes, custom programmable quantized resistors, and mesoscopic valley filters. In some cases, device scalability is crucial, as seen in fields like resistance metrology, where graphene devices are required to accommodate currents of the order 100 mu A to be compatible with existing infrastructure. However, fabrication of these devices still poses many difficulties. In this work, unusual quantized resistances are observed in epitaxial graphene Corbino p-n junction devices held at the nu=2Motivated by recent developments on the fabrication and control of semiconductor-based quantum dots, we theoretically study a finite system of tunnel-coupled quantum dots with the electrons interacting through the long-range Coulomb interaction. When the interelectron separation is large and the quantum dot confinement potential is weak, the system behaves as an effective Wigner crystal with a period determined by the electron average density with considerable electron hopping throughout the system. For stronger periodic confinement potentials, however, the system makes a crossover to a Mott-type ground state where the electrons are completely localized at the individual dots with little interdot tunneling. In between these two phases, the system is essentially a strongly correlated electron liquid with intersite electron hopping constrained by strong Coulomb interaction. We characterize this Wigner-Mott-liquid quantum crossover with detailed numerical finite-size diagonalization calculations of the coupled interacting quantum dot system, showing that these phases can be smoothly connected by tuning the system parameters. Experimental feasibility of observing such a hopping-tuned Wigner-Mott-liquid crossover in currently available semiconductor quantum dots is discussed. In particular, we connect our theoretical results to recent quantum-dot-based quantum emulation experiments where a collective Coulomb blockade was demonstrated. We discuss realistic disorder effects on our theoretical findings. One conclusion of our work is that experiments must explore lower density quantum dot arrays in order to clearly observe the Wigner phase although the Mott-liquid crossover phenomenon should already manifest itself in the currently available quantum dot arrays. We also suggest a direct experimental electron density probe, such as atomic force microscopy or scanning tunneling microscopy, for a clear observation of the effective Wigner crystal phase.

}, doi = {10.1103/PhysRevResearch.2.023060}, author = {Vu, DinhDuy and Das Sarma, Sankar} } @article { ISI:000505979700006, title = {Collisions of room-temperature helium with ultracold lithium and the van der Waals bound state of HeLi}, journal = {Phys. Rev. A}, volume = {101}, number = {1}, year = {2020}, month = {JAN 6}, pages = {012702}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We have computed the thermally averaged total, elastic rate coefficient for the collision of a room-temperature helium atom with an ultracold lithium atom. This rate coefficient has been computed as part of the characterization of a cold-atom vacuum sensor based on laser-cooled Li-6 or Li-7 atoms that will operate in the ultrahigh-vacuum (p < 10(-6) Pa) and extreme-high-vacuum (p < 10(-10) Pa) regimes. The analysis involves computing the X (2) Sigma(+) HeLi Born-Oppenheimer potential followed by the numerical solution of the relevant radial Schrodinger equation. The potential is computed using a single-reference-coupled-cluster electronic-structure method with basis sets of different completeness in order to characterize our uncertainty budget. We predict that the rate coefficient for a 300 K helium gas and a 1 mu K Li gas is 1.467(13) x 10(-9) cm(3)/s for He-4 + Li-6 and 1.471(13) x 10(-9) cm(3)/s for He-4 + Li-7, where the numbers in parentheses are the one-standard-deviation uncertainties in the last two significant digits. We quantify the temperature dependence as well. Finally, we evaluate the s-wave scattering length and binding of the single van der Waals bound state of HeLi. We predict that this weakly bound level has a binding energy of -0.0064(43) x hc cm(-1) and -0.0122(67) x hc cm(-1) for He-4 + Li-6 and He-4 + Li-7, respectively. The calculated binding energy of He-4 + Li-7 is consistent with the sole experimental determination.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.101.012702}, author = {Makrides, Constantinos and Barker, Daniel S. and Fedchak, James A. and Scherschligt, Julia and Eckel, Stephen and Tiesinga, Eite} } @article { ISI:000507490800005, title = {Combining experiments and relativistic theory for establishing accurate radiative quantities in atoms: The lifetime of the P-2(3/2) state in Ca-40(+)}, journal = {Phys. Rev. A}, volume = {101}, number = {1}, year = {2020}, month = {JAN 14}, pages = {012509}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We report a precise determination of the lifetime of the (4p) P-2(3/2) state of Ca-40(+), tau(p3/2) = 6.639(42) ns, using a combination of measurements of the induced light shift and scattering rate on a single trapped ion. Good agreement with the result of a recent high-level theoretical calculation, 6.69(6) ns {[}M. S. Safronova et al., Phys. A 83, 012503 (2011)], but a 6-sigma discrepancy with the most precise previous experimental value, 6.924(19) ns {[}J. Jin et al., Phys. Rev. Lett. 70, 3213 (1993)], is found. To corroborate the consistency and accuracy of the new measurements, relativistically corrected ratios of reduced-dipole-matrix elements are used to directly compare our result with a recent result for the P-1/2 state, yielding a good agreement. The application of the present method to precise determinations of radiative quantities of molecular systems is discussed.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.101.012509}, author = {Meir, Ziv and Sinhal, Mudit and Safronova, Marianna S. and Willitsch, Stefan} } @article { ISI:000571724100001, title = {A comparison of g((1)) (tau), g((3/2))(tau), and g((2))(tau) for radiation from harmonic oscillators in Brownian motion with a coherent background}, journal = {Phys. Scr.}, volume = {95}, number = {10}, year = {2020}, month = {OCT}, pages = {104001}, publisher = {IOP PUBLISHING LTD}, type = {Article}, abstract = {We compare the field-fieldg((1))(tau), intensity-fieldg((3/2))(tau), and intensity-intensityg((2))(tau) correlation functions for models that are of relevance in astrophysics. We obtain expressions for the general case of a chaotic radiation, where the amplitude is Rician based on a model with an ensemble of harmonic oscillators in Brownian motion. We obtain the signal to noise ratios for two methods of measurement. The intensity-field correlation function signal to noise ratio scales with the first power of vertical bar g((1))(tau). This is in contrast with the well-established result of g((2))(t)((2))(tau) which goes as the square of vertical bar g((1))(tau)vertical bar.}, keywords = {astrophysics, field correlation, intensity correlation, intensity-field correlation, Statistical Physics}, issn = {0031-8949}, doi = {10.1088/1402-4896/abac37}, author = {Siciak, A. and Hugbart, M. and Guerin, W. and Kaiser, R. and Orozco, L. A.} } @article { ISI:000581926500001, title = {Confinement of an alkaline-earth element in a grating magneto-optical trap}, journal = {Rev. Sci. Instrum.}, volume = {91}, number = {10}, year = {2020}, month = {OCT 1}, pages = {103202}, publisher = {AMER INST PHYSICS}, type = {Article}, abstract = {We demonstrate a compact magneto-optical trap (MOT) of alkaline-earth atoms using a nanofabricated diffraction grating chip. A single input laser beam, resonant with the broad S-1(0) -> P-1(1) transition of strontium, forms the MOT in combination with three diffracted beams from the grating chip and a magnetic field produced by permanent magnets. A differential pumping tube limits the effect of the heated, effusive source on the background pressure in the trapping region. The system has a total volume of around 2.4 l. With our setup, we have trapped up to 5 x 10(6) Sr-88 atoms at a temperature of similar to 6 mK, and with a trap lifetime of similar to 1 s. Our results will aid the effort to miniaturize quantum technologies based on alkaline-earth atoms.}, issn = {0034-6748}, doi = {10.1063/5.0019551}, author = {Sitaram, A. and Elgee, P. K. and Campbell, G. K. and Klimov, N. N. and Eckel, S. and Barker, D. S.} } @article { ISI:000506811300021, title = {Counting on Majorana modes}, journal = {Science}, volume = {367}, number = {6474}, year = {2020}, month = {JAN 10}, pages = {145}, publisher = {AMER ASSOC ADVANCEMENT SCIENCE}, type = {Article}, issn = {0036-8075}, doi = {10.1126/science.aaz9589}, author = {Sau, Jay} } @article { ISI:000534162700004, title = {Creating solitons with controllable and near-zero velocity in Bose-Einstein condensates}, journal = {Phys. Rev. A}, volume = {101}, number = {5}, year = {2020}, month = {MAY 20}, pages = {053629}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Established techniques for deterministically creating dark solitons in repulsively interacting atomic Bose-Einstein condensates (BECs) can only access a narrow range of soliton velocities. Because velocity affects the stability of individual solitons and the properties of soliton-soliton interactions, this technical limitation has hindered experimental progress. Here we create dark solitons in highly anisotropic cigar-shaped BECs with arbitrary position and velocity by simultaneously engineering the amplitude and phase of the condensate wave function, improving upon previous techniques which explicitly manipulated only the condensate phase. The single dark soliton solution present in true one-dimensional (1D) systems corresponds to the kink soliton in anisotropic three-dimensional systems and is joined by a host of additional dark solitons, including vortex ring and solitonic vortex solutions. We readily create dark solitons with speeds from zero to half the sound speed. The observed soliton oscillation frequency suggests that we imprinted solitonic vortices, which for our cigar-shaped system are the only stable solitons expected for these velocities. Our numerical simulations of 1D BECs show this technique to be equally effective for creating kink solitons when they are stable. We demonstrate the utility of this technique by deterministically colliding dark solitons with domain walls in two-component spinor BECs.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.101.053629}, author = {Fritsch, A. R. and Lu, Mingwu and Reid, G. H. and Pineiro, A. M. and Spielman, I. B.} } @article { ISI:000510386300003, title = {Critical local moment fluctuations and enhanced pairing correlations in a cluster Anderson model}, journal = {Phys. Rev. B}, volume = {101}, number = {1}, year = {2020}, month = {JAN 31}, pages = {014452}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {The appearance of unconventional superconductivity near heavy-fermion quantum critical points (QCPs) motivates investigation of pairing correlations close to a {\textquoteleft}{\textquoteleft}beyond Landau{{\textquoteright}{\textquoteright}} Kondo-destruction QCP. We focus on a two-Anderson-impurity cluster in which Kondo destruction is induced by a pseudogap in the conduction-electron density of states. Analysis via continuous-time quantum Monte Carlo and the numerical renormalization group reveals a previously unstudied QCP that both displays the critical-local moment fluctuations characteristic of Kondo destruction and leads to a strongly enhanced singlet-pairing susceptibility. Our results provide insights into the mechanism for superconductivity in quantum critical metals.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.101.014452}, author = {Cai, Ang and Pixley, J. H. and Ingersent, Kevin and Si, Qimiao} } @article {liang_cryspnet_2020, title = {{CRYSPNet}: {Crystal} structure predictions via neural networks}, journal = {Phys. Rev. Mater.}, volume = {4}, number = {12}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {dec}, abstract = {Structure is the most basic and important property of crystalline solids; it determines directly or indirectly most materials characteristics. However, predicting crystal structure of solids remains a formidable and not fully solved problem. Standard theoretical tools for this task are computationally expensive and at times inaccurate. Here we present an alternative approach utilizing machine learning for crystal structure prediction. We developed a tool called Crystal Structure Prediction Network (CRYSPNet) that can predict the Bravais lattice, space group, and lattice parameters of an inorganic material based only on its chemical composition. CRYSPNet consists of a series of neural network models, using as inputs predictors aggregating the properties of the elements constituting the compound. It was trained and validated on more than 100 000 entries from the Inorganic Crystal Structure Database. The tool demonstrates robust predictive capability and outperforms alternative strategies by a large margin. It can be used both as an independent prediction engine and as a method to generate candidate structures for further computational and/or experimental validation.

}, issn = {2475-9953}, doi = {10.1103/PhysRevMaterials.4.123802}, author = {Liang, Haotong and Stanev, Valentin and Kusne, A. Gilad and Takeuchi, Ichiro} } @article {tran_destructive_2020, title = {Destructive {Error} {Interference} in {Product}-{Formula} {Lattice} {Simulation}, journal = {Phys. Rev. Lett.}, volume = {124}, number = {22}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {jun}, abstract = {Quantum computers can efficiently simulate the dynamics of quantum systems. In this Letter, we study the cost of digitally simulating the dynamics of several physically relevant systems using the first-order product-formula algorithm. We show that the errors from different Trotterization steps in the algorithm can interfere destructively, yielding a much smaller error than previously estimated. In particular, we prove that the total error in simulating a nearest-neighbor interacting system of n sites for time t using the first-order product formula with r time slices is O(nt/r + nt(3)/r(2)) when nt(2)/r is less than a small constant. Given an error tolerance epsilon, the error bound yields an estimate of max\{O(n(2)t/epsilon), O(n(2)t(3/2)/epsilon(1/2))\} for the total gate count of the simulation. The estimate is tighter than previous bounds and matches the empirical performance observed in Childs et al. [Proc. Natl. Acad. Sci. U.S.A. 115, 9456 (2018)]. We also provide numerical evidence for potential improvements and conjecture an even tighter estimate for the gate count.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.124.220502}, author = {Tran, Minh C. and Chu, Su-Kuan and Su, Yuan and Childs, Andrew M. and Gorshkov, V, Alexey} } @article { ISI:000569266900003, title = {Detecting Acoustic Blackbody Radiation with an Optomechanical Antenna}, journal = {Phys. Rev. Lett.}, volume = {125}, number = {12}, year = {2020}, month = {SEP 15}, pages = {120603}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Nanomechanical systems are generally embedded in a macroscopic environment where the sources of thermal noise are difficult to pinpoint. We engineer a silicon nitride membrane optomechanical resonator such that its thermal noise is acoustically driven by a spatially well-defined remote macroscopic bath. This bath acts as an acoustic blackbody emitting and absorbing acoustic radiation through the silicon substrate. Our optomechanical system acts as a sensitive detector for the blackbody temperature and for photoacoustic imaging. We demonstrate that the nanomechanical mode temperature is governed by the blackbody temperature and not by the local material temperature of the resonator. Our work presents a route to mitigate self-heating effects in optomechanical thermometry and other quantum optomechanics experiments, as well as acoustic communication in quantum information.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.125.120603}, author = {Singh, Robinjeet and Purdy, Thomas P.} } @article { ISI:000557736300003, title = {Detection of the Lowest-Lying Odd-Parity Atomic Levels in Actinium}, journal = {Phys. Rev. Lett.}, volume = {125}, number = {7}, year = {2020}, month = {AUG 10}, pages = {073001}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Two lowest-energy odd-parity atomic levels of actinium, 7s(2)7p(2)P(1/2)(0), 7s(2)7p(2)P(3/)(2)(0), were observed via two-step resonant laser-ionization spectroscopy and their respective energies were measured to be 7477.36(4) and 12 276.59(2) cm(-1). The lifetimes of these states were determined as 668(11) and 255(7) ns, respectively. In addition, we observed the effect of the hyperfine structure on the line for the transition to P-2(3)/2(0). These properties were calculated using a hybrid approach that combines configuration interaction and coupled-cluster methods, in good agreement with the experiment. The data are of relevance for understanding the complex atomic spectra of actinides and for developing efficient laser cooling and ionization schemes for actinium, with possible applications for high-purity medical-isotope production and future fundamental physics experiments.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.125.073001}, author = {Zhang, Ke and Studer, Dominik and Weber, Felix and Gadelshin, Vadim M. and Kneip, Nina and Raeder, Sebastian and Budker, Dmitry and Wendt, Klaus and Kieck, Tom and Porsev, Sergey G. and Cheung, Charles and Safronova, Marianna S. and Kozlov, Mikhail G.} } @article {wilson_disorder_2020, title = {Disorder in twisted bilayer graphene}, journal = {Phys. Rev. Res.}, volume = {2}, number = {2}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {jun}, abstract = {We develop a theory for a type of disorder in condensed matter systems arising from local twist-angle fluctuations in two strongly coupled van der Waals monolayers twisted with respect to each other to create a flat-band moire superlattice. The paradigm of {\textquotedblleft}twist-angle disorder{\textquotedblright} arises from the currently ongoing intense research activity in the physics of twisted bilayer graphene. In experimental samples of pristine twisted bilayer graphene, which are nominally free of impurities and defects, the main source of disorder is believed to arise from the unavoidable and uncontrollable nonuniformity of the twist angle across the sample. To address this physics of twist-angle disorder, we develop a real-space, microscopic model of twisted bilayer graphene where the angle enters as a free parameter. In particular, we focus on the size of single-particle energy gaps separating the miniband from the rest of the spectrum, the Van Hove peaks, the renormalized Dirac cone velocity near charge neutrality, and the minibandwidth. We find that the energy gaps and minibandwidth are strongly affected by disorder while the renormalized velocity remains virtually unchanged. We discuss the implications of our results for the ongoing experiments on twisted bilayer graphene. Our theory is readily generalized to future studies of twist-angle disorder effects on all electronic properties of moire superlattices created by twisting two coupled van der Waals materials with respect to each other.}, doi = {10.1103/PhysRevResearch.2.023325}, author = {Wilson, Justin H. and Fu, Yixing and Das Sarma, S. and Pixley, J. H.} } @article { ISI:000541476900001, title = {Dissipative Kerr Solitons in a III-V Microresonator}, journal = {Laser Photon. Rev.}, volume = {14}, number = {8}, year = {2020}, month = {AUG}, pages = {2000022}, publisher = {WILEY-V C H VERLAG GMBH}, type = {Article}, abstract = {Stable microresonator Kerr soliton frequency combs in a III-V platform (AlGaAs on SiO2) are demonstrated through quenching of thermorefractive effects by cryogenic cooling to temperatures between 4 and 20 K. This cooling reduces the resonator{\textquoteright}s thermorefractive coefficient, whose room-temperature value is an order of magnitude larger than that of other microcomb platforms like Si3N4, SiO2, and AlN, by more than two orders of magnitude, and makes soliton states adiabatically accessible. Realizing such phase-stable soliton operation is critical for applications that fully exploit the ultra-high effective nonlinearity and high optical quality factors exhibited by this platform.}, keywords = {frequency combs, GaAs, microcombs, nanophotonics, Nonlinear optics, soliton}, issn = {1863-8880}, doi = {10.1002/lpor.202000022},}, author = {Moille, Gregory and Chang, Lin and Xie, Weiqiang and Rao, Ashutosh and Lu, Xiyuan and Davanco, Marcelo and Bowers, John E. and Srinivasan, Kartik} } @article {tran_dynamical_2020, title = {Dynamical {Josephson} effects in {NbSe2}, journal = {Phys. Rev. Res.}, volume = {2}, number = {4}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {nov}, abstract = {The study of superconducting materials that also possess nontrivial correlations or interactions remains an active frontier of condensed matter physics. NbSe2 belongs to this class of superconductors and recent research has focused on the two-dimensional properties of this layered, superconducting material. Often, electronic transport measurements are used to investigate the superconducting properties of these materials, hence it is key to obtain a thorough understanding of transport in these systems. We investigate the transition between the superconducting and resistive state using radio-frequency AC excitation. Despite being a single piece of superconductor, the devices show novel dynamical Josephson effects behavior reminiscent of the AC Josephson effect observed in Josephson junctions. Detailed analysis uncovers the origin of this effect, identifying two types of vortex motion that categorize the transition to the normal state. Our results shed light on the nature of superconductivity in this material, unearthing exotic phenomena by exploiting nonequilibrium superconducting effects in atomically thin materials.}, doi = {10.1103/PhysRevResearch.2.043204}, author = {Tran, S. and Sell, J. and Williams, J. R.} } @article { ISI:000509352500053, title = {Effect of imperfect homodyne visibility on multi-spatial-mode two-mode squeezing measurements}, journal = {Opt. Express}, volume = {28}, number = {1}, year = {2020}, month = {JAN 6}, pages = {652-664}, publisher = {OPTICAL SOC AMER}, type = {Article}, abstract = {We study the effect of homodyne detector visibility on the measurement of quadrature squeezing for a spatially multi-mode source of two-mode squeezed light. Sources like optical parametric oscillators (OPO) typically produce squeezing in a single spatial mode because the nonlinear medium is within a mode-selective optical cavity. For such a source, imperfect interference visibility in the homodyne detector couples in additional vacuum noise, which can be accounted for by introducing an equivalent loss term. In a free-space multi-spatial-mode system imperfect homodyne detector visibility can couple in uncorrelated squeezed modes, and hence can cause faster degradation of the measured squeezing. We show experimentally the dependence of the measured squeezing level on the visibility of homodyne detectors used to probe two-mode squeezed states produced by a free space tour-wave mixing process in Rb-85 vapor, and also demonstrate that a simple theoretical model agrees closely with the experimental data. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement}, issn = {1094-4087}, doi = {10.1364/OE.379033}, author = {Gupta, Prasoon and Speirs, Rory W. and Jones, Kevin M. and Lett, Paul D.} } @article { ISI:000552791500001, title = {The effect of strain on tunnel barrier height in silicon quantum devices}, journal = {J. Appl. Phys.}, volume = {128}, number = {2}, year = {2020}, month = {JUL 14}, pages = {024303}, publisher = {AMER INST PHYSICS}, type = {Article}, abstract = {Semiconductor quantum dot (QD) devices experience a modulation of the band structure at the edge of lithographically defined gates due to mechanical strain. This modulation can play a prominent role in the device behavior at low temperatures, where QD devices operate. Here, we develop an electrical measurement of strain based on I ( V ) characteristics of tunnel junctions defined by aluminum and titanium gates. We measure relative differences in the tunnel barrier height due to strain consistent with experimentally measured coefficients of thermal expansion ( alpha) that differ from the bulk values. Our results show that the bulk parameters commonly used for simulating strain in QD devices incorrectly capture the impact of strain. The method presented here provides a path forward toward exploring different gate materials and fabrication processes in silicon QDs in order to optimize strain.}, issn = {0021-8979}, doi = {10.1063/5.0010253}, author = {Stein, Ryan M. and Stewart, Jr., M. D.} } @article {19016, title = {Efficient photoinduced second-harmonic generation in silicon nitride photonics}, journal = {Nature Photonics}, year = {2020}, month = {11/2020}, abstract = {Silicon photonics lacks a second-order nonlinear optical (Ï‡(2)) response in general, because the typical constituent materials are centrosymmetric and lack inversion symmetry, which prohibits Ï‡(2) nonlinear processes such as second-harmonic generation (SHG). Here, we realize high SHG efficiency in silicon photonics by combining a photoinduced effective Ï‡(2) nonlinearity with resonant enhancement and perfect phase matching. We show a conversion efficiency of (2,500\ {\textpm}\ 100)\%\ W-1 that is two to four orders of magnitude larger than previous field-induced SHG works. In particular, our devices realize milliwatt-level SHG output powers with up to (22\ {\textpm}\ 1)\% power conversion efficiency. This demonstration is a breakthrough in realizing efficient Ï‡(2) processes in silicon photonics, and paves the way for further integration of self-referenced frequency combs and optical frequency references.

}, issn = {1749-4893}, doi = {10.1038/s41566-020-00708-4}, url = {https://doi.org/10.1038/s41566-020-00708-4}, author = {Lu, Xiyuan and Moille, Gregory and Rao, Ashutosh and Westly, Daron A. and Srinivasan, Kartik} } @conference {lu_efficient_2020, title = {Efficient second harmonic generation in a {Si3N4} microring}, booktitle = {Conference on Lasers and Electro-Optics (CLEO)}, series = {Conference on {Lasers} and {Electro}-{Optics}}, year = {2020}, note = {Backup Publisher: IEEE ISSN: 2160-9020 Type: Proceedings Paper}, publisher = {IEEE}, organization = {IEEE}, abstract = {We demonstrate efficient second harmonic generation in a silicon nitride microring, through perfect phase matching of a photogalvanic DC-field-induced chi((2)) process. The efficiency of 2,500 \%/W is {\textgreater} 100 x larger than the previous record in silicon photonics. (c) 2020 The Author(s)

}, isbn = {978-1-943580-76-7}, author = {Lu, Xiyuan and Moille, Gregory and Rao, Ashutosh and Westly, Daron and Li, Qing and Srinivasan, Kartik} } @conference {lu_efficient_2020-1, title = {Efficient widely-separated optical parametric oscillation}, booktitle = {Conference on Lasers and Electro-Optics (CLEO)}, series = {Conference on {Lasers} and {Electro}-{Optics}}, year = {2020}, note = {Backup Publisher: IEEE ISSN: 2160-9020 Type: Proceedings Paper}, publisher = {IEEE}, organization = {IEEE}, abstract = {We demonstrate the first widely-separated optical parametric oscillation in silicon nanophotonics, with milliwatt-level threshold power that is {\textgreater} 50 times smaller than other widely-separated OPOs. This demonstration is promising for on-chip visible light generation. (C) 2020 The Author(s)

}, isbn = {978-1-943580-76-7}, author = {Lu, Xiyuan and Moille, Gregory and Singh, Anshuman and Li, Qing and Westly, Daron and Rao, Ashutosh and Yu, Su-Peng and Briles, Travis C. and Drake, Tara and Papp, Scott B. and Srinivasan, Kartik} } @article {das_sarma_electron-phonon_2020, title = {Electron-phonon and electron-electron interaction effects in twisted bilayer graphene}, journal = {Ann. Phys.}, volume = {417}, year = {2020}, note = {Place: 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA Publisher: ACADEMIC PRESS INC ELSEVIER SCIENCE Type: Article}, month = {jun}, abstract = {By comparing with recently available experimental data from several groups, we critically discuss the manifestation of continuum many body interaction effects in twisted bilayer graphene (tBLG) with small twist angles and low carrier densities, which arise naturally within the Dirac cone approximation for the non-interacting band structure. We provide two specific examples of such continuum many body theories: one involving electron-phonon interaction and one involving electron-electron interaction. In both cases, the experimental findings are only partially quantitatively consistent with rather clear-cut leading-order theoretical predictions based on well-established continuum many body theories. We provide a critical discussion, based mainly on the currently available tBLG experimental data, on possible future directions for understanding many body renormalization involving electron-phonon and electron-electron interactions in the system. One definitive conclusion based on the comparison between theory and experiment is that the leading order 1-loop perturbative renormalization group theory completely fails to account for the electron-electron interaction effects in the strong-coupling limit of flatband moire tBLG system near the magic twist angle even at low doping where the Dirac cone approximation should apply. By contrast, approximate nonperturbative theoretical results based on Borel-Pade resummation or 1/N expansion seem to work well compared with experiments, indicating rather small interaction corrections to Fermi velocity or carrier effective mass. For electron-phonon interactions, however, the leading-order continuum theory works well except when van Hove singularities in the density of states come into play. (C) 2020 Elsevier Inc. All rights reserved.}, issn = {0003-4916}, doi = {10.1016/j.aop.2020.168193}, author = {Das Sarma, Sankar and Wu, Fengcheng} } @article {mueller_energy-based_2020, title = {Energy-{Based} {Plasmonicity} {Index} to {Characterize} {Optical} {Resonances} in {Nanostructures}}, journal = {J. Phys. Chem. C}, volume = {124}, number = {44, SI}, year = {2020}, note = {Place: 1155 16TH ST, NW, WASHINGTON, DC 20036 USA Publisher: AMER CHEMICAL SOC Type: Article}, month = {nov}, pages = {24331{\textendash}24343}, abstract = {Resonances sustained by plasmonic nanoparticles provide extreme electric field confinement and enhancement into the deep subwavelength domain for a plethora of applications. Recent progress in nanofabrication made it even possible to tailor the properties of nanoparticles consisting of only a few hundred atoms. These nanoparticles support both single-particle-like resonances and collective plasmonic charge density oscillations. Prototypical systems sustaining both features are graphene nanoantennas. In pushing the frontier of nanoscience, traditional identification, and classification of such resonances is at stake again. We show that in such nanostructures, the concerted electron cloud oscillation in real space does not necessarily come along with collective dynamics of conduction band electrons in energy space. This unveils an urgent need for a discussion of how a plasmon in nanostructures should be defined. Here, we propose to define it relying on energy space dynamics. The unambiguous identification of the plasmonic nature of a resonance is crucial to find out whether desirable plasmon-assisted features, such as frequency conversion processes, can be expected from a resonance. We elaborate an energy-based figure of merit that classifies the nature of resonances in nanostructures, motivated by tight binding simulations with a toy model consisting of a linear chain of atoms. We apply afterward the proposed figure of merit to a doped hexagonal graphene nanoantenna, which is known to support plasmons in the near infrared and single-particle-like transitions in the visible.

}, issn = {1932-7447}, doi = {10.1021/acs.jpcc.0c07964}, author = {Mueller, Marvin M. and Kosik, Miriam and Pelc, Marta and Bryant, Garnett W. and Ayuela, Andres and Rockstuhl, Carsten and Slowik, Karolina} } @article { ISI:000573650200006, title = {Enhanced transport of spin-orbit-coupled Bose gases in disordered potentials}, journal = {Phys. Rev. A}, volume = {102}, number = {3}, year = {2020}, month = {SEP 17}, pages = {033325}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Anderson localization is a single-particle localization phenomena in disordered media that is accompanied by an absence of diffusion. Spin-orbit coupling (SOC) describes an interaction between a particle{\textquoteright}s spin and its momentum that directly affects its energy dispersion, for example, creating dispersion relations with gaps and multiple local minima We show theoretically that combining one-dimensional spin-orbit coupling with a transverse Zeeman field suppresses the effects of disorder, thereby increasing the localization length and conductivity. This increase results from a suppression of backscattering between states in the gap of the SOC dispersion relation. Here, we focus specifically on the interplay of disorder from an optical speckle potential and SOC generated by two-photon Raman processes in quasi-one-dimensional Bose-Einstein condensates. We first describe backscattering by using a Fermi golden rule approach, and then numerically confirm this picture by solving the time-dependent one-dimensional Gross-Pitaevskii equation for a weakly interacting Bose-Einstein condensate with SOC and disorder. We find that on the tens of millisecond timescale of typical cold atom experiments moving in harmonic traps, initial states with momentum in the zero-momentum SOC gap evolve with negligible backscattering, while without SOC these same states rapidly localize.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.102.033325}, author = {Yue, Y. and de Melo, C. A. R. Sa and Spielman, I. B.} } @article {winer_exponential_2020, title = {Exponential {Ramp} in the {Quadratic} {Sachdev}-{Ye}-{Kitaev} {Model}}, journal = {Phys. Rev. Lett.}, volume = {125}, number = {25}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {dec}, abstract = {A long period of linear growth in the spectral form factor provides a universal diagnostic of quantum chaos at intermediate times. By contrast, the behavior of the spectral form factor in disordered integrable many-body models is not well understood. Here we study the two-body Sachdev-Ye-Kitaev model and show that the spectral form factor features an exponential ramp, in sharp contrast to the linear ramp in chaotic models. We find a novel mechanism for this exponential ramp in terms of a high-dimensional manifold of saddle points in the path integral formulation of the spectral form factor. This manifold arises because the theory enjoys a large symmetry group. With finite nonintegrable interaction strength, these delicate symmetries reduce to a relative time translation, causing the exponential ramp to give way to a linear ramp.

}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.125.250602}, author = {Winer, Michael and Jian, Shao-Kai and Swingle, Brian} } @article { ISI:000526522000042, title = {Extreme ultraviolet photon conversion efficiency of tetraphenyl butadiene}, journal = {Appl. Optics}, volume = {59}, number = {4}, year = {2020}, month = {FEB 1}, pages = {1217-1224}, publisher = {OPTICAL SOC AMER}, type = {Article}, abstract = {Extreme ultraviolet (EUV) radiation can be converted to visible light using tetraphenyl butadiene (TPB) as a phosphor. 1 mu m films of TPB were prepared using thermal vapor deposition of the pure material and by spin coating suspensions of TPB in high-molecular-weight polystyrene/toluene solutions. Calibrated sources and detectors were used to determine the effective photon conversion efficiency of the films for incident EUV radiation in the wavelength range of 125 nm <= lambda <= 200 nm. After exposure to atmosphere, the efficiency of the vapor-deposited films decreased significantly, while the efficiency of the spin-coated films remained unchanged. The production of TPB films by spin coating offers the advantages of simplicity and long-term stability. (C) 2020 Optical Society of America}, issn = {1559-128X}, doi = {10.1364/AO.380185}, author = {Graybill, Joshua R. and Shahi, Chandra B. and Coplan, Michael A. and Thompson, Alan K. and Vest, Robert E. and Clark, Charles W.} } @article {hurst_feedback_2020, title = {Feedback induced magnetic phases in binary {Bose}-{Einstein} condensates}, journal = {Phys. Rev. Res.}, volume = {2}, number = {4}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {dec}, abstract = {Weak measurement in tandem with real-time feedback control is a new route toward engineering novel nonequilibrium quantum matter. Here we develop a theoretical toolbox for quantum feedback control of multicomponent Bose-Einstein condensates (BECs) using backaction-limited weak measurements in conjunction with spatially resolved feedback. Feedback in the form of a single-particle potential can introduce effective interactions that enter into the stochastic equation governing system dynamics. The effective interactions are tunable and can be made analogous to Feshbach resonances-spin independent and spin dependent-but without changing atomic scattering parameters. Feedback cooling prevents runaway heating due to measurement backaction and we present an analytical model to explain its effectiveness. We showcase our toolbox by studying a two-component BEC using a stochastic mean-field theory, where feedback induces a phase transition between easy-axis ferromagnet and spin-disordered paramagnet phases. We present the steady-state phase diagram as a function of intrinsic and effective spin-dependent interaction strengths. Our result demonstrates that closed-loop quantum control of Bose-Einstein condensates is a powerful tool for quantum engineering in cold-atom systems.}, doi = {10.1103/PhysRevResearch.2.043325}, author = {Hurst, Hilary M. and Guo, Shangjie and Spielman, I. B.} } @article { ISI:000571392500002, title = {Fermion parity gap and exponential ground state degeneracy of the one-dimensional Fermi gas with intrinsic attractive interaction}, journal = {Phys. Rev. B}, volume = {102}, number = {12}, year = {2020}, month = {SEP 21}, pages = {125135}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We examine the properties of a one-dimensional (1D) Fermi gas with attractive intrinsic (Hubbard) interactions in the presence of spin-orbit coupling and Zeeman field by numerically computing the pair binding energy, excitation gap, and susceptibility to local perturbations using the density matrix renormalization group. Such a system can, in principle, be realized in a system of ultracold atoms confined in a 1D optical lattice. We note that, in the presence of spatial interfaces introduced by a smooth parabolic potential, the pair binding and excitation energy of the system decays exponentially with the system size, pointing to the existence of an exponential ground state degeneracy, and is consistent with recent works. However, the susceptibility of the ground state degeneracy of this number-conserving system to local impurities indicates that the energy gap vanishes as a power law with the system size in the presence of local perturbations. We compare this system with the more familiar system of an Ising antiferromagnet in the presence of a transverse field realized with Rydberg atoms and argue that the exponential splitting in the clean number-conserving 1D Fermi system is similar to a phase with only conventional order.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.102.125135}, author = {Roy, Monalisa Singh and Kumar, Manoranjan and Sau, Jay D. and Tewari, Sumanta} } @article { ISI:000579337200002, title = {Fermi-surface topology and renormalization of bare ellipticity in an interacting anisotropic electron gas}, journal = {Phys. Rev. B}, volume = {102}, number = {16}, year = {2020}, month = {OCT 19}, pages = {161114}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We investigate effects of electron-electron interactions on the shape of the Fermi surface in an anisotropic two-dimensional electron gas using the {\textquoteleft}{\textquoteleft}RPA-GW{{\textquoteright}{\textquoteright}} self-energy approximation. We find that the interacting Fermi surface deviates from an ellipse but not in an arbitrary way. The interacting Fermi surface has only two qualitatively distinct shapes for most values of r(s). The Fermi surface undergoes two distinct transitions between these two shapes as r(s) increases. For larger r(s), the degree of the deviation from an ellipse rapidly increases, but, in general, our theory provides a justification for the widely used elliptical Fermi-surface approximation, even for the interacting system, since the nonelliptic corrections are quantitatively rather small except for very large r(s).}, issn = {2469-9950}, doi = {10.1103/PhysRevB.102.161114}, author = {Ahn, Seongjin and Das Sarma, S.} } @article {alavirad_ferromagnetism_2020, title = {Ferromagnetism and its stability from the one-magnon spectrum in twisted bilayer graphene}, journal = {Phys. Rev. B}, volume = {102}, number = {23}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {dec}, abstract = {We study ferromagnetism and its stability in twisted bilayer graphene. We work with a Hubbard-like interaction that corresponds to the screened Coulomb interaction in a well-defined limit where the Thomas-Fermi screening length l(TF) is much larger than monolayer graphene{\textquoteright}s lattice spacing l(g) {\textless}{\textless} l(TF) and much smaller than the moire superlattice{\textquoteright}s spacing l(TF) {\textless}{\textless} l(moire). We show that in the perfectly flat band {\textquotedblleft}chiral{\textquotedblright} limit and at filling fractions +/- 3/4, the saturated ferromagnetic (spin- and valley-polarized) states are ideal ground-state candidates in the large band-gap limit. By assuming a large enough substrate (hBN) induced sublattice potential, the same argument can be applied to filling fractions +/- 1/4. We estimate the regime of stability of the ferromagnetic phase around the chiral limit by studying the exactly calculated spectrum of one-magnon excitations. The instability of the ferromagnetic state is signaled by a negative magnon excitation energy. This approach allows us to deform the results of the idealized chiral model (by increasing the bandwidth and/or modified interactions) toward more realistic systems. Furthermore, we use the low-energy part of the exact one-magnon spectrum to calculate the spin-stiffness of the Goldstone modes throughout the ferromagnetic phase. The calculated value of spin-stiffness can determine the excitation energy of charged skyrmions.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.102.235123}, author = {Alavirad, Yahya and Sau, Jay} } @article { ISI:000529804100001, title = {Ferromagnetism and superconductivity in twisted double bilayer graphene}, journal = {Phys. Rev. B}, volume = {101}, number = {15}, year = {2020}, month = {APR 30}, pages = {155149}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We present a theory of competing ferromagnetic and superconducting orders in twisted double bilayer graphene. In our theory, ferromagnetism is induced by Coulomb repulsion, while superconductivity with intervalley equal-spin pairing can be mediated by electron-acoustic phonon interactions. We calculate the transition temperatures for ferromagnetism and superconductivity as a function of moire band filling factor, and find that superconducting domes can appear on both the electron and hole sides of the ferromagnetic insulator at half filling. We show that the ferromagnetic insulating gap has a dome shape dependence on the layer potential difference, which provides an explanation to the experimental observation that the ferromagnetic insulator only develops over a finite range of external displacement field. We also verify the stability of the half filled ferromagnetic insulator against two types of collective excitations, i.e., spin magnons and valley magnons.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.101.155149}, author = {Wu, Fengcheng and Das Sarma, Sankar} } @article { ISI:000552576600008, title = {Fidelity of a sequence of SWAP operations on a spin chain}, journal = {Phys. Rev. B}, volume = {102}, number = {3}, year = {2020}, month = {JUL 27}, pages = {035439}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We consider the {\textquoteleft}{\textquoteleft}transport{{\textquoteright}{\textquoteright}} of the state of a spin across a Heisenberg-coupled spin chain via the use of repeated SWAP gates, starting with one of two states-one in which the leftmost spin is down and the others up, and one in which the leftmost two spins are in a singlet state (i.e., they are entangled), and the others are again all up. More specifically, we transport the state of the leftmost spin in the first case and the next-to-leftmost spin in the second to the other end of the chain, and then back again. We accomplish our SWAP operations here by increasing the exchange coupling between the two spins that we operate on from a base value J to a larger value J(SWAP) for a time t = pi(h) over bar /4J(SWAP). We determine the fidelity of this sequence of operations in a number of situations-one in which only nearest-neighbor coupling exists between spins and there is no magnetic dipole-dipole coupling or noise (the most ideal case), one in which we introduce next-nearest-neighbor coupling, but none of the other effects, and one in which all of these effects are present. In the last case, the noise is assumed to be quasistatic, i.e., the exchange couplings are each drawn from a Gaussian distribution, truncated to only nonnegative values. We plot the fidelity as a function of JSWAP to illustrate various effects, namely crosstalk due to coupling to other spins, as well as noise, that are detrimental to our ability to perform a SWAP operation. Our theory should be useful to the ongoing experimental efforts in building semiconductor-based spin quantum computer architectures.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.102.035439}, author = {Throckmorton, Robert E. and Das Sarma, S.} } @article { ISI:000536153200001, title = {Figures of merit for quantum transducers}, journal = {Quantum Sci. Technol.}, volume = {5}, number = {3}, year = {2020}, month = {JUL}, pages = {034009}, publisher = {IOP PUBLISHING LTD}, type = {Article}, abstract = {Recent technical advances have sparked renewed interest in physical systems that couple simultaneously to different parts of the electromagnetic spectrum, thus enabling transduction of signals between vastly different frequencies at the level of single quanta. Such hybrid systems have demonstrated frequency conversion of classical signals and have the potential of enabling quantum state transfer, e.g., between superconducting circuits and traveling optical signals. This article describes a simple approach for the theoretical characterization of the performance of quantum transducers. Given that, in practice, one cannot attain ideal one-to-one quantum conversion, we explore how imperfections impact the performance of the transducer in various scenarios. We quantify how knowledge of the well-established transducer parameters signal transfer efficiency eta and added noise N suffices to assess its performance in a variety of transduction schemes ranging from classical signal detection to applications for quantum information processing.}, keywords = {quantum sensing, quantum transduction, transduction}, issn = {2058-9565}, doi = {10.1088/2058-9565/ab8962}, author = {Zeuthen, Emil and Schliesser, Albert and Sorensen, Anders S. and Taylor, Jacob M.} } @article { ISI:000535764500002, title = {Filter-free single-photon quantum dot resonance fluorescence in an integrated cavity-waveguide device}, journal = {Optica}, volume = {7}, number = {5}, year = {2020}, month = {MAY 20}, pages = {380-385}, publisher = {OPTICAL SOC AMER}, type = {Article}, abstract = {Semiconductor quantum dots embedded in micropillar cavities are excellent emitters of single photons when pumped resonantly. Often, the same spatial mode is used to both resonantly excite a quantum-dot state and to collect the emitted single photons, requiring cross polarization to reduce the uncoupled scattered laser light. This inherently reduces the source brightness to 50\%. Critically, for some quantum applications the total efficiency from generation to detection must be over 50\%. Here, we demonstrate a resonant-excitation approach to creating single photons that is free of any cross polarization, and in fact any filtering whatsoever. It potentially increases single-photon rates and collection efficiencies, and simplifies operation. This integrated device allows us to resonantly excite single quantum-dot states in several cavities in the plane of the device using connected waveguides, while the cavity-enhanced single-photon fluorescence is directed vertically (off-chip) in a Gaussian mode. We expect this design to be a prototype for larger chip-scale quantum photonics. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement}, issn = {2334-2536}, doi = {10.1364/OPTICA.382273}, author = {Huber, Tobias and Davanco, Marcelo and Muller, Markus and Shuai, Yichen and Gazzano, Olivier and Solomon, Glenn S.} } @article {sau_anyons_2020, title = {From anyons to {Majoranas}}, journal = {Nat. Rev. Phys.}, volume = {2}, number = {12}, year = {2020}, note = {Place: CAMPUS, 4 CRINAN ST, LONDON, N1 9XW, ENGLAND Publisher: SPRINGERNATURE Type: Editorial Material}, month = {dec}, pages = {667{\textendash}668}, abstract = {Key advances Beam-splitter and interferometric measurements in the quantum Hall regime provide the strongest experimental proof to date of exotic anyonic particles. Individual states inside superconducting vortices, called Caroli-de Gennes-Matricon states, have been experimentally observed in low-density topological superconductors. Access to the Caroli-de Gennes-Matricon states provides a new platform in which anyonic particles may be braided and detected in three dimensional topological superconductors. Anyons, particles that are neither bosons nor fermions, were predicted in the 1980s, but strong experimental evidence for the existence of the simplest type of anyons has only emerged this year. Further theoretical and experimental advances promise to nail the existence of more exotic types of anyons, such as Majorana fermions, which would make topological quantum computation possible. Strong experimental evidence for the existence of the simplest type of anyons (particles that are neither bosons nor fermions) has emerged this year. The next step is to uncover more exotic types of anyons, such as Majorana fermions.

}, doi = {10.1038/s42254-020-00251-9}, author = {Sau, Jay and Simon, Steven and Vishveshwara, Smitha and Williams, James R.} } @article { ISI:000562277400001, title = {Frustration-induced supersolid phases of extended Bose-Hubbard model in the hard-core limit}, journal = {J. Phys.-Condes. Matter}, volume = {32}, number = {45}, year = {2020}, month = {OCT 28}, pages = {455401}, publisher = {IOP PUBLISHING LTD}, type = {Article}, abstract = {We investigate exotic supersolid phases in the extended Bose-Hubbard model with infinite projected entangled-pair state, numerical exact diagonalization, and mean-field theory. We demonstrate that many different supersolid phases can be generated by changing signs of hopping terms, and the interactions along with the frustration of hopping terms are important to stabilize those supersolid states. We argue the effect of frustration introduced by the competition of hopping terms in the supersolid phases from the mean-field point of view. This helps to give a clearer picture of the background mechanism for underlying superfluid/supersolid states to be formed. With this knowledge, we predict and realize thed-wave superfluid, which shares the same pairing symmetry with high-T(c)materials, and its extended phases. We believe that our results contribute to preliminary understanding for desired target phases in the real-world experimental systems.}, keywords = {Bose-Hubbard model, exact diagonalization, phase diagrams, projected entangled pair states, superfluids, supersolids}, issn = {0953-8984}, doi = {10.1088/1361-648X/aba383}, author = {Tu, Wei-Lin and Wu, Huan-Kuang and Suzuki, Takafumi} } @article { ISI:000506582800005, title = {Generic quantized zero-bias conductance peaks in superconductor-semiconductor hybrid structures}, journal = {Phys. Rev. B}, volume = {101}, number = {2}, year = {2020}, month = {JAN 8}, pages = {024506}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We show theoretically that quantized zero-bias conductance peaks should be ubiquitous in superconductor-semiconductor hybrids by employing a zero-dimensional random matrix model with continuous tuning parameters. We demonstrate that a normal metal-superconductor (NS) junction conductance spectra can be generically obtained in this model replicating all features seen in recent experimental results. The theoretical quantized conductance peaks, which explicitly do not arise from spatially isolated Majorana zero modes, are easily found by preparing a contour plot of conductance over several independent tuning parameters, mimicking the effect of Zeeman splitting and voltages on gates near the junction. This suggests that, even stable apparently quantized conductance peaks need not correspond to isolated Majorana modes; rather, the a priori expectation should be that such quantized peaks generically occupy a significant fraction of the high-dimensional tuning parameter space that characterizes the NS tunneling experiments.

}, issn = {2469-9950}, doi = {10.1103/PhysRevB.101.024506}, author = {Pan, Haining and Cole, William S. and Sau, Jay D. and Das Sarma, Sankar} } @article { ISI:000524530000001, title = {Ground-state energy estimation of the water molecule on a trapped-ion quantum computer}, journal = {npj Quantum Inform.}, volume = {6}, number = {1}, year = {2020}, month = {APR 3}, pages = {33}, publisher = {NATURE PUBLISHING GROUP}, type = {Article}, abstract = {Quantum computing leverages the quantum resources of superposition and entanglement to efficiently solve computational problems considered intractable for classical computers. Examples include calculating molecular and nuclear structure, simulating strongly interacting electron systems, and modeling aspects of material function. While substantial theoretical advances have been made in mapping these problems to quantum algorithms, there remains a large gap between the resource requirements for solving such problems and the capabilities of currently available quantum hardware. Bridging this gap will require a co-design approach, where the expression of algorithms is developed in conjunction with the hardware itself to optimize execution. Here we describe an extensible co-design framework for solving chemistry problems on a trapped-ion quantum computer and apply it to estimating the ground-state energy of the water molecule using the variational quantum eigensolver (VQE) method. The controllability of the trapped-ion quantum computer enables robust energy estimates using the prepared VQE ansatz states. The systematic and statistical errors are comparable to the chemical accuracy, which is the target threshold necessary for predicting the rates of chemical reaction dynamics, without resorting to any error mitigation techniques based on Richardson extrapolation.}, doi = {10.1038/s41534-020-0259-3}, author = {Nam, Yunseong and Chen, Jwo-Sy and Pisenti, Neal C. and Wright, Kenneth and Delaney, Conor and Maslov, Dmitri and Brown, Kenneth R. and Allen, Stewart and Amini, Jason M. and Apisdorf, Joel and Beck, Kristin M. and Blinov, Aleksey and Chaplin, Vandiver and Chmielewski, Mika and Collins, Coleman and Debnath, Shantanu and Hudek, Kai M. and Ducore, Andrew M. and Keesan, Matthew and Kreikemeier, Sarah M. and Mizrahi, Jonathan and Solomon, Phil and Williams, Mike and Wong-Campos, Jaime David and Moehring, David and Monroe, Christopher and Kim, Jungsang} } @conference {singh_high-q_2020, title = {High-{Q} {Nanomechanical} {Resonators} for {Optomechanical} {Sensing} {Beyond} the {Standard} {Quantum} {Limit}}, booktitle = {Conference on Lasers and Electro-Optics (CLEO)}, series = {Conference on {Lasers} and {Electro}-{Optics}}, year = {2020}, note = {Backup Publisher: IEEE ISSN: 2160-9020 Type: Proceedings Paper}, publisher = {IEEE}, organization = {IEEE}, abstract = {We fabricate high-stress silicon and silicon-nitride based nanomechanical string resonators to study quantum optomechanical interactions. We use phononic band-gap engineering techniques to minimize mechanical energy dissipation in the out-of-plane defect mode of the resonator. (C) 2020 The Author(s)

}, isbn = {978-1-943580-76-7}, author = {Singh, Robinjeet and Purdy, Thomas P.} } @article {kuehn_high_2020, title = {High {Resolution} {Photoexcitation} {Measurements} {Exacerbate} the {Long}-{Standing} {Fe} {XVII} {Oscillator} {Strength} {Problem}, journal = {Phys. Rev. Lett.}, volume = {124}, number = {22}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {jun}, abstract = {For more than 40 years, most astrophysical observations and laboratory studies of two key soft x-ray diagnostic 2p - 3d transitions, 3C and 3D, in Fe XVII ions found oscillator strength ratios f(3C)/f(3D) disagreeing with theory, but uncertainties had precluded definitive statements on this much studied conundrum. Here, we resonantly excite these lines using synchrotron radiation at PETRA III, and reach, at a millionfold lower photon intensities, a 10 times higher spectral resolution, and 3 times smaller uncertainty than earlier work. Our final result of f(3C)/f(3D) = 3.09(8)(6) supports many of the earlier clean astrophysical and laboratory observations, while departing by five sigmas from our own newest large-scale ab initio calculations, and excluding all proposed explanations, including those invoking nonlinear effects and population transfers.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.124.225001}, author = {Kuehn, Steffen and Shah, Chintan and Lopez-Urrutia, Jose R. Crespo and Fujii, Keisuke and Steinbruegge, Rene and Stierhof, Jakob and Togawa, Moto and Harman, Zoltan and Oreshkina, Natalia S. and Cheung, Charles and Kozlov, Mikhail G. and Porsev, Sergey G. and Safronova, Marianna S. and Berengut, Julian C. and Rosner, Michael and Bissinger, Matthias and Ballhausen, Ralf and Hell, Natalie and Park, SungNam and Chung, Moses and Hoesch, Moritz and Seltmann, Joern and Surzhykov, Andrey S. and Yerokhin, Vladimir A. and Wilms, Joern and Porter, F. Scott and Stoehlker, Thomas and Keitel, Christoph H. and Pfeifer, Thomas and Brown, V, Gregory and Leutenegger, Maurice A. and Bernitt, Sven} } @article { ISI:000565455100005, title = {Higher-order topological Dirac superconductors}, journal = {Phys. Rev. B}, volume = {102}, number = {9}, year = {2020}, month = {SEP 3}, pages = {094503}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We introduce higher-order topological Dirac superconductor (HOTDSC) as a gapless topological phase of matter in three dimensions, which extends the notion of Dirac phase to a higher-order topological version. Topologically distinct from the traditional topological superconductors and known Dirac superconductors, a HOTDSC features Majorana hinge modes between adjacent surfaces, which are direct consequences of the symmetry-protected higher-order band topology manifesting in the system. Specifically, we show that rotational, spatial inversion, and time-reversal symmetries together protect the coexistence of bulk Dirac nodes and hinge Majorana modes in a seamless way. We define a set of topological indices that fully characterizes the HOTDSC. We further show that a practical way to realize the HOTDSC phase is to introduce unconventional odd-parity pairing to a three-dimensional Dirac semimetal while preserving the necessary symmetries. As a concrete demonstration of our idea, we construct a corresponding minimal lattice model for HOTDSC obeying the symmetry constraints. Our model exhibits the expected topological invariants in the bulk and the defining spectroscopic features on an open geometry, as we explicitly verify both analytically and numerically. Remarkably, the HOTDSC phase offers an example of a {\textquoteleft}{\textquoteleft}higher-order topological quantum critical point, which enables realizations of various higher-order topological phases under different symmetry-breaking patterns. In particular, by breaking the inversion symmetry of a HOTDSC, we arrive at a higher-order Weyl superconductor, which is yet another gapless topological state that exhibits hybrid higher-order topology.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.102.094503}, author = {Zhang, Rui-Xing and Hsu, Yi-Ting and Das Sarma, S.} } @article {chou_hofstadter_2020, title = {Hofstadter butterfly and {Floquet} topological insulators in minimally twisted bilayer graphene}, journal = {Phys. Rev. Res.}, volume = {2}, number = {3}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {aug}, abstract = {We theoretically study the Hofstadter butterfly of a triangular network model in minimally twisted bilayer graphene. The band structure manifests periodicity in energy, mimicking that of Floquet systems. The butterfly diagrams provide fingerprints of the model parameters and reveal the hidden band topology. In a strong magnetic field, we establish that minimally twisted bilayer graphene realizes low-energy Floquet topological insulators (FTIs) carrying zero Chern number, while hosting chiral edge states in bulk gaps. We identify the FTIs by analyzing the nontrivial spectral flow in the Hofstadter butterfly, and by explicitly computing the chiral edge states. Our theory paves the way for an effective practical realization of FTIs in equilibrium solid-state systems.}, doi = {10.1103/PhysRevResearch.2.033271}, author = {Chou, Yang-Zhi and Wu, Fengcheng and Das Sarma, Sankar} } @article {elshaari_hybrid_2020, title = {Hybrid integrated quantum photonic circuits}, journal = {Nat. Photonics}, volume = {14}, number = {5}, year = {2020}, note = {Place: MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND Publisher: NATURE PUBLISHING GROUP Type: Review}, month = {may}, pages = {285{\textendash}298}, abstract = {The Review summarizes the progress of hybrid quantum photonics integration in terms of its important design considerations and fabrication approaches, and highlights some successful realizations of key physical resources for building integrated quantum devices, such as quantum teleporters, quantum repeaters and quantum simulators. Recent developments in chip-based photonic quantum circuits have radically impacted quantum information processing. However, it is challenging for monolithic photonic platforms to meet the stringent demands of most quantum applications. Hybrid platforms combining different photonic technologies in a single functional unit have great potential to overcome the limitations of monolithic photonic circuits. Our Review summarizes the progress of hybrid quantum photonics integration, discusses important design considerations, including optical connectivity and operation conditions, and highlights several successful realizations of key physical resources for building a quantum teleporter. We conclude by discussing the roadmap for realizing future advanced large-scale hybrid devices, beyond the solid-state platform, which hold great potential for quantum information applications.}, issn = {1749-4885}, doi = {10.1038/s41566-020-0609-x}, author = {Elshaari, Ali W. and Pernice, Wolfram and Srinivasan, Kartik and Benson, Oliver and Zwiller, Val} } @article {zhiqiang_hyperfine-mediated_2020, title = {Hyperfine-mediated effects in a {Lu}+ optical clock}, journal = {Phys. Rev. A}, volume = {102}, number = {5}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {nov}, abstract = {We consider hyperfine-mediated effects for clock transitions in Lu-176(+). Mixing of fine-structure levels due to the hyperfine interaction brings about modifications to the Lande g-factors and the quadrupole moment for a given state. Explicit expressions are derived for both the g-factor and quadrupole corrections, for which leading-order terms arise from the nuclear magnetic dipole coupling. High accuracy measurements of the g-factors for the S-1(0) and D-3(1) hyperfine levels are carried out, and they provide an experimental determination of the leading-order correction terms.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.102.052834}, author = {Zhiqiang, Zhang and Arnold, K. J. and Kaewuam, R. and Safronova, M. S. and Barrett, M. D.} } @article {16901, title = {Imaging viscous flow of the Dirac fluid in graphene}, journal = {Nature}, volume = {583}, year = {2020}, month = {Jul}, pages = {537-541}, abstract = {The electron{\textendash}hole plasma in charge-neutral graphene is predicted to realize a quantum critical system in which electrical transport features a universal hydrodynamic description, even at room temperature1,2. This quantum critical {\textquoteleft}Dirac fluid{\textquoteright} is expected to have a shear viscosity close to a minimum bound3,4, with an interparticle scattering rate saturating1 at the Planckian time, the shortest possible timescale for particles to relax. Although electrical transport measurements at finite carrier density are consistent with hydrodynamic electron flow in graphene5{\textendash}8, a clear demonstration of viscous flow at the charge-neutrality point remains elusive. Here we directly image viscous Dirac fluid flow in graphene at room temperature by measuring the associated stray magnetic field. Nanoscale magnetic imaging is performed using quantum spin magnetometers realized with nitrogen vacancy centres in diamond. Scanning single-spin and wide-field magnetometry reveal a parabolic Poiseuille profile for electron flow in a high-mobility graphene channel near the charge-neutrality point, establishing the viscous transport of the Dirac fluid. This measurement is in contrast to the conventional uniform flow profile imaged in a metallic conductor and also in a low-mobility graphene channel. Via combined imaging and transport measurements, we obtain viscosity and scattering rates, and observe that these quantities are comparable to the universal values expected at quantum criticality. This finding establishes a nearly ideal electron fluid in charge-neutral, high-mobility graphene at room temperature4. Our results will enable the study of hydrodynamic transport in quantum critical fluids relevant to strongly correlated electrons in high-temperature superconductors9. This work also highlights the capability of quantum spin magnetometers to probe correlated electronic phenomena at the nanoscale.

}, issn = {1476-4687}, doi = {10.1038/s41586-020-2507-2}, url = {https://doi.org/10.1038/s41586-020-2507-2}, author = {Ku, Mark J. H. and Zhou, Tony X. and Li, Qing and Shin, Young J. and Shi, Jing K. and Burch, Claire and Anderson, Laurel E. and Pierce, Andrew T. and Xie, Yonglong and Hamo, Assaf and Vool, Uri and Zhang, Huiliang and Casola, Francesco and Taniguchi, Takashi and Watanabe, Kenji and Fogler, Michael M. and Kim, Philip and Yacoby, Amir and Walsworth, Ronald L.} } @article {li_improved_2020, title = {Improved coupled-mode theory for high-index-contrast photonic platforms}, journal = {Phys. Rev. A}, volume = {102}, number = {6}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {dec}, abstract = {Coupled-mode theory (CMT) has been widely used in optics and photonics design. Despite its popularity, several different formulations of CMT exist in the literature, and their applicable range is not entirely clear, in particular when it comes to high-index-contrast photonics platforms. Here we propose an improved formulation of CMT and demonstrate its superior performance through numerical simulations that compare CMT-derived quantities with supermode calculations and full wave propagation simulations. In particular, application of the improved CMT to asymmetric waveguides reveals a necessary correction in the conventional phase matching condition for high-index-contrast systems, which could lead to more accurate photonic circuit designs involving asymmetric elements.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.102.063506}, author = {Li, Qing and Moille, Gregory and Taheri, Hossein and Adibi, Ali and Srinivasan, Kartik} } @article {hwang_impurity-scattering-induced_2020, title = {Impurity-scattering-induced carrier transport in twisted bilayer graphene}, journal = {Phys. Rev. Res.}, volume = {2}, number = {1}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {mar}, abstract = {We theoretically calculate the impurity-scattering-induced resistivity of twisted bilayer graphene at low twist angles where the graphene Fermi velocity is strongly suppressed. We consider, as a function of carrier density, twist angle, and temperature, both long-ranged Coulomb scattering and short-ranged defect scattering within a Boltzmann theory relaxation time approach. For experimentally relevant disorder, impurity scattering contributes a resistivity comparable to (much larger than) the phonon scattering contribution at high (low) temperatures. Decreasing twist angle leads to larger resistivity, and in general, the resistivity increases (decreases) with increasing temperature (carrier density). Inclusion of the van Hove singularity in the theory leads to a strong increase in the resistivity at higher densities, where the chemical potential is close to a van Hove singularity, leading to an apparent density-dependent plateau-type structure in the resistivity, which has been observed in recent transport experiments. We also show that the Matthiessen{\textquoteright}s rule is strongly violated in twisted bilayer graphene at low twist angles.}, doi = {10.1103/PhysRevResearch.2.013342}, author = {Hwang, E. H. and Das Sarma, S.} } @conference {rao_integrated_2020, title = {Integrated {Photonic} {Interposers} for {Processing} {Octave}-{Spanning} {Microresonator} {Frequency} {Combs}}, booktitle = {Conference on Lasers and Electro-Optics (CLEO)}, series = {Conference on {Lasers} and {Electro}-{Optics}}, year = {2020}, note = {Backup Publisher: IEEE ISSN: 2160-9020 Type: Proceedings Paper}, publisher = {IEEE}, organization = {IEEE}, abstract = {We demonstrate multiple silicon-nitride nanophotonic elements for on-chip processing of octave-spanning microresonator frequency combs. Dichroic filters, multimode interferometers, and tunable add-drop microring filters are shown along with soliton microcombs generated on a bilayer photonic chip. (C) 2020 The Author(s)

}, isbn = {978-1-943580-76-7}, author = {Rao, Ashutosh and Moille, Gregory and Lu, Xiyuan and Sacchetto, Davide and Geiselmann, Michael and Zervas, Michael and Papp, Scott and Bowers, John and Srinivasan, Kartik} } @conference {dutta_integrated_2020, title = {An {Integrated} {Photonic} {Platform} for {Rare}-{Earth} {Ions} in {Thin} {Film} {Lithium} {Niobate}}, booktitle = {Conference on Lasers and Electro-Optics (CLEO)}, series = {Conference on {Lasers} and {Electro}-{Optics}}, year = {2020}, note = {Backup Publisher: IEEE ISSN: 2160-9020 Type: Proceedings Paper}, publisher = {IEEE}, organization = {IEEE}, abstract = {We demonstrate an integrated photonic platform for rare earth ions in thin film lithium niobate. The ions in the thin film retain bulk like optical properties. This paves way for a new generation of highly scalable, active optoelectronic devices with applications to both classical and quantum optics. (C) 2020 The Author(s)

}, isbn = {978-1-943580-76-7}, author = {Dutta, Subhojit and Goldschmidt, Elizabeth A. and Barik, Sabyasachi and Saha, Uday and Waks, Edo} } @article { ISI:000507151600097, title = {Integrated Photonic Platform for Rare-Earth Ions in Thin Film Lithium Niobate}, journal = {Nano Lett.}, volume = {20}, number = {1}, year = {2020}, month = {JAN}, pages = {741-747}, publisher = {AMER CHEMICAL SOC}, type = {Article}, abstract = {Rare-earth ion ensembles doped in single crystals are a promising materials system with widespread applications in optical signal processing, lasing, and quantum information processing. Incorporating rare-earth ions into integrated photonic devices could enable compact lasers and modulators, as well as on-chip optical quantum memories for classical and quantum optical applications. To this end, a thin film single crystalline wafer structure that is compatible with planar fabrication of integrated photonic devices would be highly desirable. However, incorporating rare-earth ions into a thin film form-factor while preserving their optical properties has proven challenging. We demonstrate an integrated photonic platform for rare-earth ions doped in a single crystalline thin film lithium niobate on insulator. The thin film is composed of lithium niobate doped with Tm3+. The ions in the thin film exhibit optical lifetimes identical to those measured in bulk crystals. We show narrow spectral holes in a thin film waveguide that require up to 2 orders of magnitude lower power to generate than previously reported bulk waveguides. Our results pave the way for scalable on-chip lasers, optical signal processing devices, and integrated optical quantum memories.}, keywords = {integrated photonics, optical signal processing, Rare-earth ions, spectral hole burning quantum information processing, thin film lithium niobate}, issn = {1530-6984}, doi = {10.1021/acs.nanolett.9b04679}, author = {Dutta, Subhojit and Goldschmidt, Elizabeth A. and Barik, Sabyasachi and Saha, Uday and Waks, Edo} } @article { ISI:000562003800006, title = {Inversion-protected Higher-order Topological Superconductivity in Monolayer WTe2}, journal = {Phys. Rev. Lett.}, volume = {125}, number = {9}, year = {2020}, month = {AUG 24}, pages = {097001}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Monolayer WTe2, a centrosymmetric transition metal dichacogenide, has recently been established as a quantum spin Hall insulator and found superconducting upon gating. Here we study the pairing symmetry and topological nature of superconducting WTe2 with a microscopic model at mean-field level. Surprisingly, we find that the spin-triplet phases in our phase diagram all host Majorana modes localized on two opposite corners. Even when the conventional pairing is favored, we find that an intermediate inplane magnetic field exceeding the Pauli limit stabilizes an unconventional equal-spin pairing aligning with the field, which also hosts Majorana corner modes. Motivated by our findings, we obtain a recipe for two-dimensional superconductors featuring {\textquoteleft}{\textquoteleft}higher-order topology{{\textquoteright}{\textquoteright}} from the boundary perspective. Generally, a superconducting inversion-symmetric quantum spin Hall material whose normal-state Fermi surface is away from high-symmetry points, such as gated monolayer WTe2, hosts Majorana corner modes if the superconductivity is parity-odd. We further point out that this higher-order phase is an inversion-protected topological crystalline superconductor and study the bulk-boundary correspondence. Finally, we discuss possible experiments for probing the Majorana corner modes. Our findings suggest superconducting monolayer WTe, is a playground for higher-order topological superconductivity and possibly the first material realization for inversion-protected Majorana corner modes without utilizing proximity effect.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.125.097001}, author = {Hsu, Yi-Ting and Cole, William S. and Zhang, Rui-Xing and Sau, Jay D.} } @conference {sabines-chesterking_klyshko_2020, title = {Klyshko efficiency optimization using a genetic algorithm}, booktitle = {Conference on Lasers and Electro-Optics (CLEO)}, series = {Conference on {Lasers} and {Electro}-{Optics}}, year = {2020}, note = {Backup Publisher: IEEE ISSN: 2160-9020 Type: Proceedings Paper}, publisher = {IEEE}, organization = {IEEE}, address = {Conference on Lasers and Electro-Optics (CLEO)}, abstract = {We use a spatial light modulator and a genetic algorithm to manipulate the spatial profile of the pump beam of a down-conversion source in order to improve its Klyshko efficiency. (c) 2020 The Author(s)

}, isbn = {978-1-943580-76-7}, author = {Sabines-Chesterking, Javier and Moreau, Paul-Antoine and McMillan, Alex and Fickler, Robert and Rarity, John and Matthews, Jonathan} } @article {jian_landau_2020, title = {Landau poles in condensed matter systems}, journal = {Phys. Rev. Res.}, volume = {2}, number = {2}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {jun}, abstract = {The existence or not of Landau poles is one of the oldest open questions in nonasymptotic quantum field theories. We investigate the Landau pole issue in two condensed matter systems whose long-wavelength physics is described by appropriate quantum field theories: the critical quantum magnet and Dirac fermions in graphene with long-range Coulomb interactions. The critical quantum magnet provides a classic example of a quantum phase transition, and it is well described by the phi(4) theory. We find that the irrelevant but symmetry-allowed couplings, such as the phi(6) potential, can significantly change the fate of the Landau pole in the emergent phi(4) theory. We obtain the coupled beta functions of a phi(4) + phi(6) potential at both small and large orders. Already from the one-loop calculation, the Landau pole is replaced by an ultraviolet fixed point. A Lipatov analysis at large orders reveals that the inclusion of a phi(6) term also has important repercussions for the high-order expansion of the beta functions. We also investigate the role of the Landau pole in a very different system: Dirac fermions in 2 + 1 dimensions with long-range Coulomb interactions, e.g., graphene. Both the weak-coupling perturbation theory up to two loops and a low-order large-N calculation show the absence of a Landau pole. Furthermore, we calculate the asymptotic expansion coefficients of the beta function. We find that the asymptotic coefficient is bounded by that of a pure bosonic phi(4) theory, and consequently graphene is free from Landau poles if the pure (4) theory does not manifest a Landau pole. We briefly discuss possible experiments that could potentially probe the existence of a Landau pole in these systems. Studying Landau poles in suitable condensed matter systems is of considerable fundamental importance since the relevant Landau pole energy scales in particle physics, whether it is quantum electrodynamics or Higgs physics, are completely unattainable.}, doi = {10.1103/PhysRevResearch.2.023310}, author = {Jian, Shao-Kai and Barnes, Edwin and Das Sarma, Sankar} } @article {kollar_line-graph_2020, title = {Line-{Graph} {Lattices}: {Euclidean} and {Non}-{Euclidean} {Flat} {Bands}, and {Implementations} in {Circuit} {Quantum} {Electrodynamics}}, journal = {Commun. Math. Phys.}, volume = {376}, number = {3}, year = {2020}, note = {Place: ONE NEW YORK PLAZA, SUITE 4600, NEW YORK, NY, UNITED STATES Publisher: SPRINGER Type: Article}, month = {jun}, pages = {1909{\textendash}1956}, abstract = {Materials science and the study of the electronic properties of solids are a major field of interest in both physics and engineering. The starting point for all such calculations is single-electron, or non-interacting, band structure calculations, and in the limit of strong on-site confinement this can be reduced to graph-like tight-binding models. In this context, both mathematicians and physicists have developed largely independent methods for solving these models. In this paper we will combine and present results from both fields. In particular, we will discuss a class of lattices which can be realized as line graphs of other lattices, both in Euclidean and hyperbolic space. These lattices display highly unusual features including flat bands and localized eigenstates of compact support. We will use the methods of both fields to show how these properties arise and systems for classifying the phenomenology of these lattices, as well as criteria for maximizing the gaps. Furthermore, we will present a particular hardware implementation using superconducting coplanar waveguide resonators that can realize a wide variety of these lattices in both non-interacting and interacting form.

}, issn = {0010-3616}, doi = {10.1007/s00220-019-03645-8}, author = {Kollar, Alicia J. and Fitzpatrick, Mattias and Sarnak, Peter and Houck, Andrew A.} } @conference {mazurek_loophole-free_2020, title = {Loophole-{Free} {Test} of {Einstein}-{Podolsky}-{Rosen} {Steering} with {One} {Bit} of {Faster}-than-{Light} {Communication}}, booktitle = {Conference on Lasers and Electro-Optics (CLEO)}, series = {Conference on {Lasers} and {Electro}-{Optics}}, year = {2020}, note = {Backup Publisher: IEEE ISSN: 2160-9020 Type: Proceedings Paper}, publisher = {IEEE}, organization = {IEEE}, abstract = {The communication cost for classically simulating Einstein-Podolsky-Rosen (EPR) steering correlations quantifies their strength. We report a loophole-free demonstration of EPR steering correlations requiring more than one faster-than-light bit to simulate. (C) 2020 The Author(s)

}, isbn = {978-1-943580-76-7}, author = {Mazurek, M. D. and Xiang, Y. and Stevens, M. J. and Bienfang, J. C. and Wayne, M. A. and Abellan, C. and Amaya, W. and Mitchell, M. W. and Mirin, R. P. and Nam, S. W. and He, Q. and Shalm, L. K. and Wiseman, H. M.} } @article { ISI:000527491100005, title = {Magic wavelength of the Ba-138(+) 6s S-2(1/2)-5d D-2(5/2) clock transition}, journal = {Phys. Rev. A}, volume = {101}, number = {4}, year = {2020}, month = {APR 22}, pages = {042507}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {The zero crossing of the dynamic differential scalar polarizability of the S-1/2 - D-5/2 clock transition in Ba-138(+) has been determined to be 459.1614(28) THz. Together with previously determined matrix elements and branching ratios, this tightly constrains the dynamic differential scalar polarizability of the clock transition over a large wavelength range (greater than or similar to 700 nm). In particular, it allows an estimate of the blackbody radiation shift of the clock transition at room temperature.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.101.042507}, author = {Chanu, S. R. and Koh, V. P. W. and Arnold, K. J. and Kaewuam, R. and Tan, T. R. and Zhang, Zhiqiang and Safronova, M. S. and Barrett, M. D.} } @article {zheng_magic_2020, title = {Magic wavelengths of the {Yb} (6s(2) {S}-1(0)-6s6p {P}-3(1)) intercombination transition}, journal = {Phys. Rev. A}, volume = {102}, number = {6}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {dec}, abstract = {We calculate and measure the magic wavelengths for the 6s(2) S-1(0)-6s6p P-3(1) intercombination transition of the neutral ytterbium atom. The calculation is performed with the ab initio configuration interaction + all-order method. The measurement is done with laser spectroscopy on cold atoms in an optical dipole trap. The magic wavelengths are determined to be 1035.68(4) nm for the pi transition (Delta m = 0) and 1036.12(3) nm for the sigma transitions (vertical bar Delta m vertical bar = 1) in agreement with the calculated values. Laser cooling on the narrow intercombination transition could achieve better results for atoms in an optical dipole trap when the trap wavelength is tuned to near the magic wavelength.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.102.062805}, author = {Zheng, T. A. and Yang, Y. A. and Safronova, M. S. and Safronova, I, U. and Xiong, Zhuan-Xian and Xia, T. and Lu, Z-T} } @article { ISI:000544124500044, title = {Magnet System for the Quantum Electromechanical Metrology Suite}, journal = {IEEE Trans. Instrum. Meas.}, volume = {69}, number = {8}, year = {2020}, month = {AUG.}, pages = {5736-5744}, publisher = {IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC}, type = {Article}, abstract = {The design of the permanent magnet system for the new quantum electromechanical metrology suite (QEMMS) is described. The QEMMS, developed at the National Institute of Standards and Technology (NIST), consists of a Kibble balance, a programmable Josephson voltage standard, and a quantum Hall resistance standard. It will be used to measure masses up to 100 g with relative uncertainties below 2 x 10(-8). The magnet system is based on the design of the NIST-4 magnet system with significant changes to adopt to a smaller Kibble balance and to overcome known practical limitations. Analytical models are provided to describe the coil-current effect and model the forces required to split the magnet into two parts to install the coil. Both models are compared to simulation results obtained with finite-element analysis and measurement results. Other aspects such as the coil design and flatness of Bl profile are considered.}, keywords = {Air gaps, Force, Kibble balance, magnet circuit, magnet system, Magnetic circuits, Magnetic noise, Magnetic shielding, mass measurement, Permanent magnets, Superconducting magnets}, issn = {0018-9456}, doi = {10.1109/TIM.2019.2959852}, author = {Marangoni, Rafael R. and Haddad, Darine and Seifert, Frank and Chao, Leon S. and Newell, David B. and Schlamminger, Stephan} } @conference {muller_measuring_2020, title = {Measuring the dark exciton in a quantum dot inside a planar microcavity using a bright state cycling transition}, booktitle = {Conference on Lasers and Electro-Optics (CLEO)}, series = {Conference on {Lasers} and {Electro}-{Optics}}, year = {2020}, note = {Backup Publisher: IEEE ISSN: 2160-9020 Type: Proceedings Paper}, publisher = {IEEE}, organization = {IEEE}, abstract = {We demonstrate the resonant excitation of a so-called dark exciton state in a quantum dot with a readout scheme based on the resonance fluorescence of the correlated bright exciton. (C) 2020 The Author(s)

}, isbn = {978-1-943580-76-7}, author = {Muller, Markus and Cao, Bin and Solomon, Glenn S.} } @article {wu_microwave{\textendash}optical_2020, title = {Microwave-to-{Optical} {Transduction} {Using} a {Mechanical} {Supermode} for {Coupling} {Piezoelectric} and {Optomechanical} {Resonators}}, journal = {Phys. Rev. Appl.}, volume = {13}, number = {1}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {jan}, abstract = {The successes of superconducting quantum circuits at local manipulation of quantum information and photonics technology at long-distance transmission of the same have spurred interest in the development of quantum transducers for efficient, low-noise, and bidirectional frequency conversion of photons between the microwave and optical domains. We propose to realize such functionality through the coupling of electrical, piezoelectric, and optomechanical resonators. The coupling of the mechanical subsystems enables formation of a resonant mechanical supermode that provides a mechanically mediated, efficient single interface to both the microwave and optical domains. The conversion process is analyzed by applying an equivalent circuit model that relates device-level parameters to overall figures of merit for conversion efficiency eta and added noise N. These can be further enhanced by proper impedance matching of the transducer to an input microwave transmission line. The performance of potential transducers is assessed through finite-element simulations, with a focus on geometries in GaAs, followed by considerations of the AlN, LiNbO3, and AlN-on-Si platforms. We present strategies for maximizing eta and minimizing N, and find that simultaneously achieving eta {\textgreater} 50\% and N {\textless} 0.5 should be possible with current technology. We find that the use of a mechanical supermode for mediating transduction is a key enabler for high-efficiency operation, particularly when paired with an appropriate microwave impedance-matching network. Our comprehensive analysis of the full transduction chain enables us to outline a development path for the realization of high-performance quantum transducers that will constitute a valuable resource for quantum information science.

}, issn = {2331-7019}, doi = {10.1103/PhysRevApplied.13.014027}, author = {Wu, Marcelo and Zeuthen, Emil and Balram, Krishna Coimbatore and Srinivasan, Kartik} } @article { ISI:000571399800001, title = {Minimal Model for Fast Scrambling}, journal = {Phys. Rev. Lett.}, volume = {125}, number = {13}, year = {2020}, month = {SEP 21}, pages = {130601}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We study quantum information scrambling in spin models with both long-range all-to-all and shortrange interactions. WC argue that a simple global, spatially homogeneous interaction together with local chaotic dynamics is sufficient to give rise to fast scrambling, which describes the spread of quantum information over the entire system in a time that is logarithmic in the system size. This is illustrated in two tractable models: (1) a random circuit with Haar random local unitaties and a global interaction and (2) a classical model of globally coupled nonlinear oscillators. We use exact numerics to provide further evidence by studying the time evolution of an out-of-time-order correlator and entanglement entropy in spin chains of intermediate sizes. Our results pave the way towards experimental investigations of fast scrambling and aspects of quantum gravity with quantum simulators.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.125.130601}, author = {Belyansky, Ron and Bienias, Przemyslaw and Kharkov, Yaroslav A. and Gorshkov, V, Alexey and Swingle, Brian} } @article { ISI:000512770000004, title = {Mobility edge and intermediate phase in one-dimensional incommensurate lattice potentials}, journal = {Phys. Rev. B}, volume = {101}, number = {6}, year = {2020}, month = {FEB 11}, pages = {064203}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We study theoretically the localization properties of two distinct one-dimensional quasiperiodic lattice models with a single-particle mobility edge (SPME) separating extended and localized states in the energy spectrum. The first one is the familiar Soukoulis-Economou trichromatic potential model with two incommensurate potentials, and the second is a system consisting of two coupled 1D Aubry-Andre chains each containing one incommensurate potential. We show that as a function of the Hamiltonian model parameters, both models have a wide single-particle intermediate phase, defined as the regime where localized and extended single-particle states coexist in the spectrum, leading to a behavior intermediate between purely extended or purely localized when the system is dynamically quenched from a generic initial state. Our results thus suggest that both systems could serve as interesting experimental platforms for studying the interplay between localized and extended states, and may provide insight into the role of the coupling of small baths to localized systems. We also calculate the Lyapunov (or localization) exponent for several incommensurate 1D models exhibiting SPME, finding that such localization critical exponents for quasiperiodic potential induced localization are nonuniversal and depend on the microscopic details of the Hamiltonian.

}, issn = {2469-9950}, doi = {10.1103/PhysRevB.101.064203}, author = {Li, Xiao and Das Sarma, Sankar} } @article { ISI:000523412800006, title = {Mobius Insulator and Higher-Order Topology in MnBi2nTe3n+1}, journal = {Phys. Rev. Lett.}, volume = {124}, number = {13}, year = {2020}, month = {APR 3}, pages = {136407}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We propose MnBi2nTe3n+1 as a magnetically tunable platform for realizing various symmetry-protected higher-order topology. Its canted antiferromagnetic phase can host exotic topological surface states with a Mobius twist that are protected by nonsymmorphic symmetry. Moreover, opposite surfaces hosting Mobius fermions are connected by one-dimensional chiral hinge modes, which offers the first material candidate of a higher-order topological Mobius insulator. We uncover a general mechanism to feasibly induce this exotic physics by applying a small in-plane magnetic field to the antiferromagnetic topological insulating phase of MnBi2nTe3n+1, as well as other proposed axion insulators. For other magnetic configurations, two classes of inversion-protected higher-order topological phases are ubiquitous in this system, which both manifest gapped surfaces and gapless chiral hinge modes. We systematically discuss their classification, microscopic mechanisms, and experimental signatures. Remarkably, the magnetic-field-induced transition between distinct chiral hinge mode configurations provides an effective {\textquoteleft}{\textquoteleft}topological magnetic switch{{\textquoteright}{\textquoteright}}.

}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.124.136407}, author = {Zhang, Rui-Xing and Wu, Fengcheng and Das Sarma, Sankar} } @article { ISI:000565086500001, title = {Multiterminal Josephson Effect}, journal = {Phys. Rev. X}, volume = {10}, number = {3}, year = {2020}, month = {SEP 2}, pages = {031051}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We report a probable observation of the dc Josephson effect in mesoscopic junctions of three and four superconductors. The devices are fabricated in a top-down fashion from a hybrid semiconductor-superconductor InAs/Al epitaxial heterostructure. In general, the critical current of an N-terminal junction is an (N - 1)-dimensional hypersurface in the space of bias currents, which can be reduced to a set of critical current contours. The geometry of critical current contours exhibits nontrivial responses to electrical gating, magnetic field, and phase bias, and it can be reproduced by the scattering formulation of the Josephson effect generalized to the case of N > 2. Besides establishing solid ground beneath a host of recent theory proposals, our experiment accomplishes an important step toward creating trijunctions of topological superconductors, essential for braiding operations.}, issn = {2160-3308}, doi = {10.1103/PhysRevX.10.031051}, author = {Pankratova, Natalia and Lee, Hanho and Kuzmin, Roman and Wickramasinghe, Kaushini and Mayer, William and Yuan, Joseph and Vavilov, Maxim G. and Shabani, Javad and Manucharyan, Vladimir E.} } @article {sinha_non-markovian_2020, title = {Non-{Markovian} {Collective} {Emission} from {Macroscopically} {Separated} {Emitters}}, journal = {Phys. Rev. Lett.}, volume = {124}, number = {4}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {jan}, abstract = {We study the collective radiative decay of a system of two two-level emitters coupled to a one-dimensional waveguide in a regime where their separation is comparable to the coherence length of a spontaneously emitted photon. The electromagnetic field propagating in the cavity-like geometry formed by the emitters exerts a retarded backaction on the system leading to strongly non-Markovian dynamics. The collective spontaneous emission rate of the emitters exhibits an enhancement or inhibition beyond the usual Dicke superradiance and subradiance due to self-consistent coherent time-delayed feedback.

}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.124.043603}, author = {Sinha, Kanupriya and Meystre, Pierre and Goldschmidt, Elizabeth A. and Fatemi, Fredrik K. and Rolston, S. L. and Solano, Pablo} } @article { ISI:000506845000012, title = {Nonequilibrium nature of nonlinear optical response: Application to the bulk photovoltaic effect}, journal = {Phys. Rev. B}, volume = {101}, number = {4}, year = {2020}, month = {JAN 13}, pages = {045201}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {The bulk photovoltaic effect is an example of a nonlinear optical response that leads to a DC current that is relevant for photovoltaic applications. In this paper, we theoretically study this effect in the presence of electron-phonon interactions. Using the response function formalism, we find that the nonlinear optical response, in general, contains three operator correlation functions, one of which is not ordered in time. This latter correlator cannot be computed from equilibrium field theory. Using a semiclassical approach instead, we show that the bulk photovoltaic effect can be attributed to the dipole moment of the generated excitons. We then confirm the validity of the semiclassical result (which agrees with the noninteracting result) for nonlinear DC response from a quantum master equation approach. From this formalism we find that, in contrast to usual linear response, the scattering rate has a strong implicit effect on the nonlinear DC response. Most interestingly, the semiclassical treatment shows that the nonlinear DC response for spatially inhomogeneous excitation profiles is strongly nonlocal and must involve the aforementioned out-of-time-ordered correlators that cannot be computed by equilibrium field theory.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.101.045201}, author = {Barik, Tamoghna and Sau, Jay D.} } @article {yoo_nonequilibrium_2020, title = {Nonequilibrium steady state phases of the interacting {Aubry}-{Andre}-{Harper} model}, journal = {Phys. Rev. B}, volume = {102}, number = {19}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {nov}, abstract = {Here, we study the phase diagram of the Aubry-Andre-Harper model in the presence of strong interactions as the strength of the quasiperiodic potential is varied. Previous work has established the existence of a many-body localized phase at a large potential strength; here, we find a rich phase diagram in the delocalized regime characterized by spin transport and unusual correlations. We calculate the nonequilibrium steady states of a boundary-driven strongly interacting Aubry-Andre-Harper model by employing the time-evolving block decimation algorithm on matrix product density operators. From these steady states, we extract spin transport as a function of system size and quasiperiodic potential strength. These data show spin transport going from superdiffusive to subdiffusive well before the localization transition; comparing to previous results, we also find that the transport transition is distinct from a transition observed in the speed of operator growth in the model. We also investigate the correlation structure of the steady state and find an unusual oscillation pattern for intermediate values of the potential strength. The unusual spin transport and quantum correlation structure suggest multiple dynamical phases between the much-studied thermal and many-body localized phases.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.102.195142}, author = {Yoo, Yongchan and Lee, Junhyun and Swingle, Brian} } @article { ISI:000510393100010, title = {Non-Markovian Collective Emission from Macroscopically Separated Emitters}, journal = {Phys. Rev. Lett.}, volume = {124}, number = {4}, year = {2020}, month = {JAN 31}, pages = {043603}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We study the collective radiative decay of a system of two two-level emitters coupled to a one-dimensional waveguide in a regime where their separation is comparable to the coherence length of a spontaneously emitted photon. The electromagnetic field propagating in the cavity-like geometry formed by the emitters exerts a retarded backaction on the system leading to strongly non-Markovian dynamics. The collective spontaneous emission rate of the emitters exhibits an enhancement or inhibition beyond the usual Dicke superradiance and subradiance due to self-consistent coherent time-delayed feedback.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.124.043603}, author = {Sinha, Kanupriya and Meystre, Pierre and Goldschmidt, Elizabeth A. and Fatemi, Fredrik K. and Rolston, S. L. and Solano, Pablo} } @article { ISI:000517213700002, title = {Nonmonotonic plasmon dispersion in strongly interacting Coulomb Luttinger liquids}, journal = {Phys. Rev. B}, volume = {101}, number = {7}, year = {2020}, month = {FEB 27}, pages = {075430}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We demonstrate that the plasmon in one-dimensional Coulomb interacting electron fluids can develop a finite-momentum maxon-roton-like nonmonotonic energy-momentum dispersion. Such an unusual nonmonotonicity arises from the strongly interacting 1/r Coulomb potential going beyond the conventional band linearization approximation used in the standard bosonization theories of Luttinger liquids. We provide details for the nonmonotonic plasmon dispersion using both bosonization and random-phase approximation theories. We also calculate the specific heat including the nonmonotonicity and discuss possibilities for observing the nonmonotonic plasmon dispersion in various physical systems, including semiconductor quantum wires, carbon nanotubes, and the twisted bilayer graphene at subdegree twist angles, which naturally realize one-dimensional domain-wall states. We provide results for several different models of long-range interaction showing that the nonomonotonic charge collective mode dispersion is a generic phenomenon in one-dimensional strongly interacting electron systems.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.101.075430}, author = {Chou, Yang-Zhi and Das Sarma, Sankar} } @article {lu_-chip_2020, title = {On-chip optical parametric oscillation into the visible: generating red, orange, yellow, and green from a near-infrared pump}, journal = {Optica}, volume = {7}, number = {10}, year = {2020}, note = {Place: 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA Publisher: OPTICAL SOC AMER Type: Article}, month = {oct}, pages = {1417{\textendash}1425}, abstract = {The on-chip generation of coherent, single-frequency laser light that can be tuned across the visible spectrum would help enable a variety of applications in spectroscopy, metrology, and quantum science. Recently, third-order optical parametric oscillation (OPO) in a microresonator has shown great promise as an efficient and scalable approach toward this end. However, considering visible light generation, so far only red light at {\textless}420 THz (near the edge of the visible band) has been reported. In this work, we overcome strong material dispersion at visible wavelengths and demonstrate on-chip OPO in a Si3N4 microresonator covering {\textgreater}130 THz of the visible spectrum, including red, orange, yellow, and green wavelengths. In particular, using an input pump laser that is scanned 5 THz in the near-infrared from 386 THz to 391 THz, the OPO output signal is tuned from the near-infrared at 395 THz to the visible at 528 THz, while the OPO output idler is tuned from the near-infrared at 378 THz to the infrared at 254 THz. The widest signal-idler separation of 274 THz is more than an octave in span and is the widest demonstrated for a nanophotonic OPO to date. More generally, our work shows how nonlinear nanophotonics can transform light from readily accessible compact near-infrared lasers to targeted visible wavelengths of interest. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement}, issn = {2334-2536}, doi = {10.1364/OPTICA.393810}, author = {Lu, Xiyuan and Moille, Gregory and Rao, Ashutosh and Westly, Daron A. and Srinivasan, Kartik} } @article { ISI:000519701600004, title = {One-dimensional few-electron effective Wigner crystal in quantum and classical regimes}, journal = {Phys. Rev. B}, volume = {101}, number = {12}, year = {2020}, month = {MAR 16}, pages = {125113}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {A system of confined charged electrons interacting via the long-range Coulomb force can form a Wigner crystal due to their mutual repulsion. This happens when the potential energy of the system dominates over its kinetic energy, i.e., at low temperatures for a classical system and at low densities for a quantum one. At T = 0, the system is governed by quantum mechanics, and hence the spatial density peaks associated with crystalline charge localization are sharpened for a lower average density. Conversely, in the classical limit of high temperatures, the crystalline spatial density peaks are suppressed (recovered) at a lower (higher) average density. In this paper, we study those two limits separately using an exact diagonalization of small one-dimensional (1D) systems containing few (\<10) electrons and propose an approximate method to connect them into a unified effective phase diagram for Wigner few-electron crystallization. The result is a qualitative quantum-classical crossover phase diagram of an effective 1D Wigner crystal. We show that although such a 1D system is at best an effective crystal with no true long-range order (and thus no real phase transition), the spatial density peaks associated with the quasicrystallization should be experimentally observable in a few-electron 1D system. We find that the effective crystalline structure slowly disappears with both the crossover average density and crossover temperature for crystallization decreasing with increasing particle number, consistent with the absence of any true long-range 1D order. Thus, an effective few-electron 1D Wigner crystal may be construed either as existing at all densities (manifesting short-range order) or as nonexisting at all densities (not manifesting any long-range order). Within one unified description, we show through exact theoretical calculations how a small 1D system interacting through the long-range Coulomb interaction could manifest effective Wigner solid behavior both in classical and quantum regimes. In fact, one peculiar aspect of the effective finite-size nature of 1D Wigner crystallization we find is that even a short-range interaction would lead to a finite-size 1D crystal, except that the crystalline order vanishes much faster with increasing system size in the short-range interacting system compared with the long-range interacting one.

}, issn = {2469-9950}, doi = {10.1103/PhysRevB.101.125113}, author = {DinhDuy Vu and Das Sarma, Sankar} } @article { ISI:000530031700002, title = {Operator Levy Flight: Light Cones in Chaotic Long-Range Interacting Systems}, journal = {Phys. Rev. Lett.}, volume = {124}, number = {18}, year = {2020}, month = {MAY 4}, pages = {180601}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We argue that chaotic power-law interacting systems have emergent limits on information propagation, analogous to relativistic light cones, which depend on the spatial dimension d and the exponent a governing the decay of interactions. Using the dephasing nature of quantum chaos, we map the problem to a stochastic model with a known phase diagram. A linear light cone results for alpha >= d + 1/2. We also provide a Levy flight (long-range random walk) interpretation of the results and show consistent numerical data for 1D long-range spin models with 200 sites.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.124.180601}, author = {Zhou, Tianci and Xu, Shenglong and Chen, Xiao and Guo, Andrew and Swingle, Brian} } @article { ISI:000548284200010, title = {Optical clocks based on the Cf15+ and Cf17+ ions}, journal = {Phys. Rev. A}, volume = {102}, number = {1}, year = {2020}, month = {JUL 6}, pages = {012802}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Recent experimental progress in cooling, trapping, and quantum logic spectroscopy of highly charged ions (HCIs) made HCIs accessible for high-resolution spectroscopy and precision fundamental studies. Based on these achievements, we explore a possibility to develop optical clocks using transitions between the ground and a low-lying excited state in Cf15+ and Cf17+ ions. Using a high-accuracy relativistic method of calculation, we predicted the wavelengths of clock transitions, calculated relevant atomic properties, and analyzed a number of systematic effects (such as the electric quadrupole, micromotion, and quadratic Zeeman shifts of the clock transitions) that affect the accuracy and stability of the optical clocks. We also calculated magnetic dipole hyperfine-structure constants of the clock states and the blackbody radiation shifts of the clock transitions.}, issn = {1050-2947}, doi = {10.1103/PhysRevA.102.012802}, author = {Porsev, S. G. and Safronova, I, U. and Safronova, M. S. and Schmidt, P. O. and Bondarev, I, A. and Kozlov, M. G. and Tupitsyn, I. I. and Cheung, C.} } @article { ISI:000542514200007, title = {Phonon scattering induced carrier resistivity in twisted double-bilayer graphene}, journal = {Phys. Rev. B}, volume = {101}, number = {24}, year = {2020}, month = {JUN 24}, pages = {245436}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {In this work we carry out a theoretical study of the phonon-induced resistivity in twisted double bilayer graphene (TDBG), in which two Bernal-stacked bilayer graphene devices are rotated relative to each other by a small angle theta. We show that at small twist angles (theta similar to 1 degrees) the effective mass of the TDBG system is greatly enhanced, leading to a drastically increased phonon-induced resistivity in the high-temperature limit where phonon scattering leads to a linearly increasing resistivity with increasing temperature. We also discuss possible implications of our theory on superconductivity in such a system and provide an order of magnitude estimation of the superconducting transition temperature.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.101.245436}, author = {Li, Xiao and Wu, Fengcheng and Das Sarma, S.} } @article { ISI:000517742600004, title = {Photonic materials in circuit quantum electrodynamics}, journal = {Nat. Phys.}, volume = {16}, number = {3}, year = {2020}, month = {MAR}, pages = {268-279}, publisher = {NATURE PUBLISHING GROUP}, type = {Review}, abstract = {Photonic synthetic materials provide an opportunity to explore the role of microscopic quantum phenomena in determining macroscopic material properties. There are, however, fundamental obstacles to overcome - in vacuum, photons not only lack mass, but also do not naturally interact with one another. Here, we review how the superconducting quantum circuit platform has been harnessed in the last decade to make some of the first materials from light. We describe the structures that are used to imbue individual microwave photons with matter-like properties such as mass, the nonlinear elements that mediate interactions between these photons, and quantum dynamic/thermodynamic approaches that can be used to assemble and stabilize strongly correlated states of many photons. We then describe state-of-the-art techniques to generate synthetic magnetic fields, engineer topological and non-topological flat bands and explore the physics of quantum materials in non-Euclidean geometries - directions that we view as some of the most exciting for this burgeoning field. Finally, we discuss upcoming prospects, and in particular opportunities to probe novel aspects of quantum thermalization and detect quasi-particles with exotic anyonic statistics, as well as potential applications in quantum information science. This Review Article surveys the physics of many-body quantum states formed by microwave photons in circuit quantum electrodynamics environments.}, issn = {1745-2473}, doi = {10.1038/s41567-020-0815-y}, author = {Carusotto, Iacopo and Houck, Andrew A. and Kollar, Alicia J. and Roushan, Pedram and Schuster, David I. and Simon, Jonathan} } @article {pan_physical_2020, title = {Physical mechanisms for zero-bias conductance peaks in {Majorana} nanowires}, journal = {Phys. Rev. Res.}, volume = {2}, number = {1}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {mar}, abstract = {Motivated by the need to understand and simulate the ubiquitous experimentally observed zero-bias conductance peaks in superconductor-semiconductor hybrid structures, we theoretically investigate the tunneling conductance spectra in one-dimensional nanowires in proximity to superconductors in a systematic manner taking into account several different physical mechanisms producing zero-bias conductance peaks. The mechanisms we consider are the presence of quantum dots, inhomogeneous potential, random disorder in the chemical potential, random fluctuations in the superconducting gap, and in the effective g factor with the self-energy renormalization induced by the parent superconductor in both short (L similar to 1 mu m) and long nanowires (L similar to 3 mu m). We classify all foregoing theoretical results for zero-bias conductance peaks into three types: the good, the bad, and the ugly, according to the physical mechanisms producing the zero-bias peaks and their topological properties. We find that, although the topological Majorana zero modes are immune to weak disorder, strong disorder ({\textquotedblright}ugly{\textquotedblright}) completely suppresses topological superconductivity and generically leads to trivial zero-bias peaks. Compared qualitatively with the extensive existing experimental results in the superconductor-semiconductor nanowire structures, we conclude that most current experiments are likely exploring trivial zero-bias peaks in the {\textquotedblleft}ugly{\textquotedblright} situation dominated by strong disorder. We also study the nonlocal end-to-end correlation measurement in both the short and long wires, and point out the limitation of the nonlocal correlation in ascertaining topological properties particularly when applied to short wires. Although we present results for {\textquotedblleft}good{\textquotedblright} and {\textquotedblleft}bad{\textquotedblright} zero-bias peaks, arising respectively from topological Majorana bound states and trivial Andreev bound states, strictly for the sake of direct comparison with the {\textquotedblleft}ugly{\textquotedblright} zero-bias conductance peaks arising from strong disorder, the main goal of the current work is to establish with a very high confidence level the real physical possibility that essentially all experimentally observed zero-bias peaks in Majorana nanowires are most likely ugly, i.e., purely induced by strong disorder, and are as such utterly nontopological. Our work clearly suggests that an essential prerequisite for any future observation of topological Majorana zero modes in nanowires is a substantialmaterials improvement of the semiconductor-superconductor hybrid systems leading to much cleaner wires.}, doi = {10.1103/PhysRevResearch.2.013377}, author = {Pan, Haining and Das Sarma, S.} } @conference {moille_post-processing_2020, title = {Post-{Processing} {Dispersion} {Engineering} of {Frequency} {Combs} {In} {Microresonator} {Addressing} {Atomic} {Clock}}, booktitle = {Conference on Lasers and Electro-Optics (CLEO)}, series = {Conference on {Lasers} and {Electro}-{Optics}}, year = {2020}, note = {Backup Publisher: IEEE ISSN: 2160-9020 Type: Proceedings Paper}, publisher = {IEEE}, organization = {IEEE}, abstract = {We study Si3N4 microresonator frequency comb to address atomic transition in the visible. We show that thanks to our air-clad system, post-process dispersion engineering through trimming allows precise control of the dispersive wave position. (C) 2020 The Author(s)

}, isbn = {978-1-943580-76-7}, author = {Moille, Gregory and Lu, Xiyuan and Rao, Ashutosh and Weedy, Daron and Srinivasan, Kartik} } @article { ISI:000555932400003, title = {Probing the relaxed relaxion at the luminosity and precision frontiers}, journal = {J. High Energy Phys.}, number = {7}, year = {2020}, month = {JUL 22}, pages = {153}, publisher = {SPRINGER}, type = {Article}, abstract = {Cosmological relaxation of the electroweak scale is an attractive scenario relaxion, is a light spin-zero field which dynamically relaxes the Higgs mass with respect to its natural large value. We show that the relaxion is generically stabilized at a special position in the field space, which leads to suppression of its mass and potentially unnatural values for the model{\textquoteright}s effective low-energy couplings. In particular, we find that the relaxion mixing with the Higgs can be several orders of magnitude above its naive naturalness bound. Low energy observers may thus find the relaxion theory being fine-tuned although the relaxion scenario itself is constructed in a technically natural way. More generally, we identify the lower and upper bounds on the mixing angle. We examine the experimental implications of the above observations at the luminosity and precision frontiers. A particular attention is given to the impressive ability of future nuclear clocks to search for rapidly oscillating scalar ultra-light dark matter, where the future projected sensitivity is presented.}, keywords = {Beyond Standard Model, Cosmology of Theories beyond the SM}, issn = {1029-8479}, doi = {10.1007/JHEP07(2020)153}, author = {Banerjee, Abhishek and Kim, Hyungjin and Matsedonskyi, Oleksii and Perez, Gilad and Safronova, Marianna S.} } @article { ISI:000519631000004, title = {Quantum Brownian motion of a particle from Casimir-Polder interactions}, journal = {Phys. Rev. A}, volume = {101}, number = {3}, year = {2020}, month = {MAR 13}, pages = {032507}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We study the fluctuation-induced dissipative dynamics of the quantized center-of-mass motion of a polarizable dielectric particle trapped near a surface. The particle{\textquoteright}s center of mass is treated as an open quantum system coupled to the electromagnetic field acting as its environment, with the resulting system dynamics described by a quantum Brownian motion master equation. The dissipation and decoherence of the particle{\textquoteright}s center of mass are characterized by the modified spectral density of the electromagnetic field that depends on surface losses and the strength of the classical trap field. Our results are relevant to experiments with levitated dielectric particles near surfaces, illustrating potential ways of mitigating fluctuation-induced decoherence while preparing such systems in macroscopic quantum states.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.101.032507}, author = {Sinha, Kanupriya and Subasi, Yigit} } @article { ISI:000576889300001, title = {Quantum geometry and stability of moire flatband ferromagnetism}, journal = {Phys. Rev. B}, volume = {102}, number = {16}, year = {2020}, month = {OCT 12}, pages = {165118}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Several moire systems created by various twisted bilayers have manifested magnetism under flatband conditions leading to enhanced interaction effects. We theoretically study stability of moire flatband ferromagnetism against collective excitations, with a focus on the effects of Bloch band quantum geometry. The spin magnon spectrum is calculated using different approaches, including Bethe-Salpeter equation, single mode approximation, and an analytical theory. One of our main results is an analytical expression for the spin stiffness in terms of the Coulomb interaction potential, the Berry curvatures, and the quantum metric tensor, where the last two quantities characterize the quantum geometry of moire bands. This analytical theory shows that Berry curvatures play an important role in stiffening the spin magnons. Furthermore, we construct an effective field theory for the magnetization fluctuations and show explicitly that skyrmion excitations bind an integer number of electrons that is proportional to the Bloch band Chern number and the skyrmion winding number.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.102.165118}, author = {Wu, Fengcheng and Das Sarma, S.} } @article { ISI:000506585800002, title = {Quantum Lifshitz criticality in a frustrated two-dimensional XY model}, journal = {Phys. Rev. B}, volume = {101}, number = {3}, year = {2020}, month = {JAN 9}, pages = {035114}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Antiferromagnetic quantum spin systems can exhibit a transition between collinear and spiral ground states, driven by frustration. Classically this is a smooth crossover and the crossover point is termed a Lifshitz point. Quantum fluctuations change the nature of the transition. In particular, it has been argued previously that in the two-dimensional (2D) case a spin liquid (SL) state is developed in the vicinity of the Lifshitz point, termed a Lifshitz SL. In the present work, using a field theory approach, we solve the Lifshitz quantum phase transition problem for the 2D frustrated XY model. Specifically, we show that, unlike the SU(2) symmetric Lifshitz case, in the XY model, the SL exists only at the critical point. At zero temperature we calculate nonuniversal critical exponents in the Neel and in the spin spiral state and relate these to properties of the SL. We also solve the transition problem at a finite temperature and discuss the role of topological excitations.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.101.035114}, author = {Kharkov, Yaroslav A. and Oitmaa, Jaan and Sushkov, Oleg P.} } @inbook {solomon_quantum_2020, title = {Quantum light from optically dressed quantum dot states in microcavities}, booktitle = {Semiconductor Quantum Science and Technology}, series = {Semiconductors and {Semimetals}}, volume = {105}, year = {2020}, note = {ISSN: 0080-8784 Journal Abbreviation: Semicond. Semimet. Type: Article; Book Chapter}, pages = {305{\textendash}346}, publisher = {ELSEVIER ACADEMIC PRESS INC}, organization = {ELSEVIER ACADEMIC PRESS INC}, isbn = {978-0-12-823773-1}, doi = {10.1016/bs.semsem.2020.10.004}, author = {Solomon, Glenn S. and Muller, Andreas and Flagg, Edward}, editor = {Cundiff, ST and Kira, M} } @conference {hao_quantum_2020, title = {Quantum {Limits} of {Optical} {Beam} {Deflection} {Measurements} of a {Nanomechanical} {Resonator}}, booktitle = {Conference on Lasers and Electro-Optics (CLEO)}, series = {Conference on {Lasers} and {Electro}-{Optics}}, year = {2020}, note = {Backup Publisher: IEEE ISSN: 2160-9020 Type: Proceedings Paper}, publisher = {IEEE}, organization = {IEEE}, abstract = {Optical lever detection is a simple and robust method to measure small displacements. We report on our experimental efforts toward reaching and surpassing the quantum backaction limits of this method when probing a high Q nanomechanical resonator. (C) 2020 The Author(s)

}, isbn = {978-1-943580-76-7}, author = {Hao, Shan and Singh, Robinjeet and Purdy, Thomas P.} } @article { ISI:000510146100001, title = {Quantum many-body scar states with emergent kinetic constraints and finite-entanglement revivals}, journal = {Phys. Rev. B}, volume = {101}, number = {2}, year = {2020}, month = {JAN 29}, pages = {024306}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We construct a set of exact, highly excited eigenstates for a nonintegrable spin-1/2 model in one dimension that is relevant to experiments on Rydberg atoms in the antiblockade regime. These states provide a new solvable example of quantum many-body scars: their sub-volume-law entanglement and equal energy spacing allow for infinitely long-lived coherent oscillations of local observables following a suitable quantum quench. While previous works on scars have interpreted such oscillations in terms of the precession of an emergent macroscopic SU(2) spin, the present model evades this description due to a set of emergent kinetic constraints in the scarred eigenstates that are absent in the underlying Hamiltonian. We also analyze the set of initial states that give rise to periodic revivals, which persist as approximate revivals on a finite timescale when the underlying model is perturbed. Remarkably, a subset of these initial states coincides with the family of area-law entangled Rokhsar-Kivelson states shown by Lesanovsky to be exact ground states for a class of models relevant to experiments on Rydberg-blockaded atomic lattices.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.101.024306}, author = {Iadecola, Thomas and Schecter, Michael} } @article { ISI:000556360300013, title = {Quantum walks and Dirac cellular automata on a programmable trapped-ion quantum computer}, journal = {Nat. Commun.}, volume = {11}, number = {1}, year = {2020}, month = {JUL 24}, pages = {3720}, publisher = {NATURE PUBLISHING GROUP}, type = {Article}, abstract = {The quantum walk formalism is a widely used and highly successful framework for modeling quantum systems, such as simulations of the Dirac equation, different dynamics in both the low and high energy regime, and for developing a wide range of quantum algorithms. Here we present the circuit-based implementation of a discrete-time quantum walk in position space on a five-qubit trapped-ion quantum processor. We encode the space of walker positions in particular multi-qubit states and program the system to operate with different quantum walk parameters, experimentally realizing a Dirac cellular automaton with tunable mass parameter. The quantum walk circuits and position state mapping scale favorably to a larger model and physical systems, allowing the implementation of any algorithm based on discrete-time quantum walks algorithm and the dynamics associated with the discretized version of the Dirac equation.}, issn = {2041-1723}, doi = {10.1038/s41467-020-17519-4}, author = {Alderete, C. Huerta and Singh, Shivani and Nhung H Nguyen and Zhu, Daiwei and Balu, Radhakrishnan and Monroe, Christopher and Chandrashekar, C. M. and Linke, Norbert M.} } @article { ISI:000555323500001, title = {Quenched vs Annealed: Glassiness from SK to SYK}, journal = {Phys. Rev. X}, volume = {10}, number = {3}, year = {2020}, month = {AUG 4}, pages = {031026}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We show that any Sachdev-Ye-Kitaev- (SYK) like model with finite-body interactions among local degrees of freedom, e.g., bosons or spins, has a fundamental difference from the standard fermionic model: The former model fails to be described by an annealed free energy at low temperature. In this respect, such models more closely resemble spin glasses. We demonstrate this by two means: first, a general theorem proving that the annealed free energy is divergent at low temperature in any model with a tensor product Hilbert space, and second, a replica treatment of two prominent examples which exhibit phase transitions from an {\textquoteleft}{\textquoteleft}annealed{{\textquoteright}{\textquoteright}} phase to a {\textquoteleft}{\textquoteleft}nonannealed{{\textquoteright}{\textquoteright}} phase as a function of the temperature. We further show that this effect appears only at O(N)th order in a 1/N expansion, even though lower-order terms misleadingly seem to converge. Our results prove that the nonbosonic nature of the particles in the SYK model is an essential ingredient for its physics, highlight connections between local models and spin glasses, and raise important questions as to the role of fermions and/or glassiness in holography.}, issn = {2160-3308}, doi = {10.1103/PhysRevX.10.031026}, author = {Baldwin, C. L. and Swingle, B.} } @article {barker_radiofrequency_2020, title = {A radiofrequency voltage-controlled current source for quantum spin manipulation}, journal = {Rev. Sci. Instrum.}, volume = {91}, number = {10}, year = {2020}, note = {Place: 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA Publisher: AMER INST PHYSICS Type: Article}, month = {oct}, abstract = {We present a wide-bandwidth, voltage-controlled current source that is easily integrated with radiofrequency magnetic field coils. Our design uses current feedback to compensate for the frequency-dependent impedance of a radiofrequency antenna. We are able to deliver peak currents greater than 100 mA over a 300 kHz to 54 MHz frequency span. The radiofrequency current source fits onto a printed circuit board smaller than 4 cm(2) and consumes less than 1.3 W of power. It is suitable for use in deployable quantum sensors and nuclear magnetic resonance systems.}, issn = {0034-6748}, doi = {10.1063/5.0011813}, author = {Barker, D. S. and Restelli, A. and Fedchak, J. A. and Scherschligt, J. and Eckel, S.} } @article {anderson_realization_2020, title = {Realization of a deeply subwavelength adiabatic optical lattice}, journal = {Phys. Rev. Res.}, volume = {2}, number = {1}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {feb}, abstract = {We propose and describe our realization of a deeply subwavelength optical lattice for ultracold neutral atoms using N resonantly Raman-coupled internal degrees of freedom. Although counterpropagating lasers with wavelength. provided two-photon Raman coupling, the resultant lattice period was lambda/2N, an N-fold reduction as compared to the conventional lambda/2 lattice period. We experimentally demonstrated this lattice built from the three F = 1 Zeeman states of a Rb-87 Bose-Einstein condensate, and generated a lattice with a lambda/6 = 132 nm period from lambda = 790 nm lasers. Lastly, we show that adding an additional rf-coupling field converts this lattice into a superlattice with N wells uniformly spaced within the original lambda/2 unit cell.}, doi = {10.1103/PhysRevResearch.2.013149}, author = {Anderson, R. P. and Trypogeorgos, D. and Valdes-Curiel, A. and Liang, Q-Y and Tao, J. and Zhao, M. and Andrijauskas, T. and Juzeliunas, G. and Spielman, I. B.} } @article { ISI:000526522500002, title = {Realization of a stroboscopic optical lattice for cold atoms with subwavelength spacing}, journal = {Phys. Rev. A}, volume = {101}, number = {4}, year = {2020}, month = {APR 17}, pages = {041603}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Optical lattices are typically created via the ac Stark shift and are limited by diffraction to periodicities >= lambda/2, where. is the wavelength of light used to create them. Lattices with smaller periodicities may be useful for many-body physics with cold atoms and can be generated by stroboscopic application of a phase-shifted lattice with subwavelength features. Here we demonstrate a lambda/4-spaced lattice by stroboscopically applying optical Kronig-Penney-like potentials which are generated using spatially dependent dark states. We directly probe the periodicity of the lambda/4-spaced lattice by measuring the average probability density of the atoms loaded into the ground band of the lattice. We measure lifetimes of atoms in this lattice and discuss the mechanisms that limit the applicability of this stroboscopic approach.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.101.041603}, author = {Tsui, T-C and Wang, Y. and Subhankar, S. and Porto, V, J. and Rolston, S. L.} } @conference {sabines-chesterking_single-emitter-sensitivity_2020, title = {Single-emitter-sensitivity in flow cytometry verified by quantum measurement}, booktitle = {Conference on Lasers and Electro-Optics (CLEO)}, series = {Conference on {Lasers} and {Electro}-{Optics}}, year = {2020}, note = {Backup Publisher: IEEE ISSN: 2160-9020 Type: Proceedings Paper}, publisher = {IEEE}, organization = {IEEE}, abstract = {We demonstrate single quantum emitter sensitivity in a flow cytometer by measuring the second order correlation function to be g((2))(0) = 0.5(1). (C) 2020 The Author(s)

}, isbn = {978-1-943580-76-7}, author = {Sabines-Chesterking, Javier and Burenkov, Ivan A. and Polyakov, V, Sergey} } @article { ISI:000531592100001, title = {Single-photon sources: Approaching the ideal through multiplexing}, journal = {Rev. Sci. Instrum.}, volume = {91}, number = {4}, year = {2020}, month = {APR 1}, pages = {041101}, publisher = {AMER INST PHYSICS}, type = {Review}, abstract = {We review the rapid recent progress in single-photon sources based on multiplexing multiple probabilistic photon-creation events. Such multiplexing allows higher single-photon probabilities and lower contamination from higher-order photon states. We study the requirements for multiplexed sources and compare various approaches to multiplexing using different degrees of freedom.}, issn = {0034-6748}, doi = {10.1063/5.0003320}, author = {Meyer-Scott, Evan and Silberhorn, Christine and Migdall, Alan} } @article { ISI:000511450000006, title = {Spatial Coherence of Spin-Orbit-Coupled Bose Gases}, journal = {Phys. Rev. Lett.}, volume = {124}, number = {5}, year = {2020}, month = {FEB 6}, pages = {053605}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Spin-orbit-coupled Bose-Einstein condensates (SOBECs) exhibit two new phases of matter, now known as the stripe and plane-wave phases. When two interacting spin components of a SOBEC spatially overlap, density modulations with periodicity given by the spin-orbit coupling strength appear. In equilibrium, these components fully overlap in the miscible stripe phase and overlap only in a domain wall in the immiscible plane-wave phase. Here we probe the density modulation present in any overlapping region with optical Bragg scattering and observe the sudden drop of Bragg scattering as the overlapping region shrinks. Using an atomic analog of the Talbot effect, we demonstrate the existence of long-range coherence between the different spin components in the stripe phase and surprisingly even in the phase-separated plane-wave phase.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.124.053605}, author = {Putra, Andika and Salces-Carcoba, F. and Yue, Yuchen and Sugawa, Seiji and Spielman, I. B.} } @article {throckmorton_spontaneous_2020, title = {Spontaneous symmetry breaking in a honeycomb lattice subject to a periodic potential}, journal = {Phys. Rev. Res.}, volume = {2}, number = {2}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {may}, abstract = {Motivated by recent developments in twisted bilayer graphene moire superlattices, we investigate the effects of electron-electron interactions in a honeycomb lattice with an applied periodic potential using a finite-temperature Wilson-Fisher momentum shell renormalization group (RG) approach. We start with a low-energy effective theory for such a system, at first giving a discussion of the most general case in which no point group symmetry is preserved by the applied potential, and then focusing on the special case in which the potential preserves a D-3 point group symmetry. As in similar studies of bilayer graphene, we find that, while the coupling constants describing the interactions diverge at or below a certain critical temperature T = T-c, it turns out that ratios of these constants remain finite and in fact provide information about what types of orders the system is becoming unstable to. However, in contrast to these previous studies, we only find isolated fixed rays, indicating that these orders are likely unstable to perturbations to the coupling constants. Our RG analysis leads to the qualitative conclusion that the emergent interaction-induced symmetry-breaking phases in this model system, and perhaps therefore by extension in twisted bilayer graphene, are generically unstable and fragile, and may thus manifest strong sample dependence.}, doi = {10.1103/PhysRevResearch.2.023225}, author = {Throckmorton, Robert E. and Das Sarma, S.} } @conference {moille_stable_2020, title = {Stable {Dissipative} {Kerr} {Solitons} in a {AlGaAs} {Microresonator} {Through} {Cryogenic} {Operation}}, booktitle = {Conference on Lasers and Electro-Optics (CLEO)}, series = {Conference on {Lasers} and {Electro}-{Optics}}, year = {2020}, note = {Backup Publisher: IEEE ISSN: 2160-9020 Type: Proceedings Paper}, publisher = {IEEE}, organization = {IEEE}, abstract = {We demonstrate stable microresonator Kerr solitons in an Al0.2Ga0.8As-on-insulator resonator thanks to cryogenic quenching of the thermorefractive effect. Reaching such a phase-stable state is a prerequisite to fully exploit the potential of this platform. (C) 2020 The Author(s)

}, isbn = {978-1-943580-76-7}, author = {Moille, Gregory and Chang, Lin and Xie, Weiqiang and Lu, Xiyuan and Davanco, Marcelo and Bowers, John E. and Srinivasan, Kartik} } @article { ISI:000533504100003, title = {State-Dependent Optical Lattices for the Strontium Optical Qubit}, journal = {Phys. Rev. Lett.}, volume = {124}, number = {20}, year = {2020}, month = {MAY 18}, pages = {203201}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We demonstrate state-dependent optical lattices for the Sr optical qubit at the tune-out wavelength for its ground state. We tightly trap excited state atoms while suppressing the effect of the lattice on ground state atoms by more than 4 orders of magnitude. This highly independent control over the qubit states removes inelastic excited state collisions as the main obstacle for quantum simulation and computation schemes based on the Sr optical qubit. Our results also reveal large discrepancies in the atomic data used to calibrate the largest systematic effect of Sr optical lattice clocks.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.124.203201}, author = {Heinz, A. and Park, A. J. and Santi, N. and Trautmann, J. and Porsev, S. G. and Safronova, M. S. and Bloch, I and Blatt, S.} } @article {saha_strongly_2020, title = {Strongly interacting spin-orbit coupled {Bose}-{Einstein} condensates in one dimension}, journal = {Phys. Rev. Res.}, volume = {2}, number = {1}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {mar}, abstract = {We theoretically study dilute superfluidity of spin-1 bosons with antiferromagnetic interactions and synthetic spin-orbit coupling (SOC) in a one-dimensional lattice. Employing a combination of density matrix renormalization group and quantum field theoretical techniques we demonstrate the appearance of a robust superfluid spin-liquid phase in which the spin sector of this spinor Bose-Einstein condensate remains quantum disordered even after introducing quadratic Zeeman and helical magnetic fields. Despite remaining disordered, the presence of these symmetry-breaking fields lifts the perfect spin-charge separation and thus the nematic correlators obey power-law behavior. We demonstrate that, at strong coupling, the SOC induces a charge density wave state that is not accessible in the presence of linear and quadratic Zeeman fields alone. In addition, the SOC induces oscillations in the spin and nematic expectation values as well as the bosonic Green{\textquoteright}s function. These nontrivial effects of an SOC are suppressed under the application of a large quadratic Zeeman field. We discuss how our results could be observed in experiments on ultracold gases of Na-23 in an optical lattice.}, doi = {10.1103/PhysRevResearch.2.013252}, author = {Saha, Siddhartha and Konig, E. J. and Lee, Junhyun and Pixley, J. H.} } @article { ISI:000505984100002, title = {Subband occupation in semiconductor-superconductor nanowires}, journal = {Phys. Rev. B}, volume = {101}, number = {4}, year = {2020}, month = {JAN 7}, pages = {045405}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Subband occupancy (i.e., the number of occupied confinement-induced subbands of the semiconductor wire) is a key physical parameter determining the topological properties of superconductor-semiconductor hybrid systems investigated in the context of the search for non-Abelian Majorana zero modes. We theoretically study the subband occupation of semiconductor nanowire devices as a function of the applied gate potential, the semiconductor-superconductor (SM-SC) work function difference, and the surface charge density by solving self-consistently the Schrodinger-Poisson equations for the conduction electrons of the semiconductor nanowire. Realistic surface charge densities, which are responsible for band bending, are shown to significantly increase the number of occupied subbands, making it difficult or impossible to reach a regime where only a few subbands are occupied. We also show that the energy separation between subbands is significantly reduced in the regime of many occupied subbands, with highly detrimental consequences for the realization and observation of robust Majorana zero modes. As a consequence, the requirements for the realization of robust topological superconductivity and Majorana zero modes should include a low value of the chemical potential, consistent with the occupation of only a few subbands. Finally, we show that the local density of states on the exposed nanowire facets provides a powerful tool for identifying a regime with many occupied subbands and is capable of providing additional critical information regarding the feasibility of Majorana physics in semiconductor-superconductor devices. In our work we address both InAs/Al and InSb/Al superconductor-nanowire hybrid systems of current experimental interest.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.101.045405}, author = {Woods, Benjamin D. and Das Sarma, Sankar and Stanescu, Tudor D.} } @article {wu_three-dimensional_2020, title = {Three-dimensional topological twistronics}, journal = {Phys. Rev. Res.}, volume = {2}, number = {2}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {apr}, abstract = {We introduce a theoretical framework for the concept of three-dimensional (3D) twistronics by developing a generalized Bloch band theory for 3D layered systems with a constant twist angle theta between successive layers. Our theory employs a nonsymmorphic symmetry that enables a precise definition of an effective out-of-plane crystal momentum, and also captures the in-plane moire pattern formed between neighboring twisted layers. To demonstrate topological physics that can be achieved through 3D twistronics, we present two examples. In the first example of chiral twisted graphite, Weyl nodes arise because of inversion-symmetry breaking, with theta-tuned transitions between type-I and type-II Weyl fermions, as well as magic angles at which the in-plane velocity vanishes. In the second example of a twisted Weyl semimetal, the twist in the lattice structure induces a chiral gauge field A that has a vortex-antivortex lattice configuration. Line modes bound to the vortex cores of the A field give rise to 3D Weyl physics in the moire scale. We also discuss possible experimental realizations of 3D twistronics.}, doi = {10.1103/PhysRevResearch.2.022010}, author = {Wu, Fengcheng and Zhang, Rui-Xing and Das Sarma, Sankar} } @article {vu_time-reversal-invariant_2020, title = {Time-reversal-invariant {C}-2-symmetric higher-order topological superconductors}, journal = {Phys. Rev. Res.}, volume = {2}, number = {4}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {nov}, abstract = {We propose a minimal lattice model for two-dimensional class DIII superconductors with C-2-protected higher-order topology. Although this class of superconductors cannot be topologically characterized by symmetry eigenvalues at high-symmetry momenta, we propose a simple Wannier-orbital-based real-space diagnosis to unambiguously capture the corresponding higher-order topology. We further identify and characterize a variety of conventional topological phases in our minimal model, including a weak topological superconductor and a nodal topological superconductor with chiral-symmetry protection. The disorder effect is also systematically studied to demonstrate the robustness of higher-order bulk-boundary correspondence. Our theory lays the groundwork for predicting and diagnosing C-2-protected higher-order topology in class DIII superconductors.}, doi = {10.1103/PhysRevResearch.2.043223}, author = {Vu, DinhDuy and Zhang, Rui-Xing and Das Sarma, S.} } @article {aasen_topological_2020, title = {Topological defect networks for fractons of all types}, journal = {Phys. Rev. Res.}, volume = {2}, number = {4}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, abstract = {Fracton phases exhibit striking behavior which appears to render them beyond the standard topological quantum field theory (TQFT) paradigm for classifying gapped quantum matter. Here, we explore fracton phases from the perspective of defect TQFTs and show that topological defect networks-networks of topological defects embedded in stratified 3+1-dimensional (3+1D) TQFTs-provide a unified framework for describing various types of gapped fracton phases. In this picture, the subdimensional excitations characteristic of fractonic matter are a consequence of mobility restrictions imposed by the defect network. We conjecture that all gapped phases, including fracton phases, admit a topological defect network description and support this claim by explicitly providing such a construction for many well-known fracton models, including the X-cube and Haah{\textquoteright}s B code. To highlight the generality of our framework, we also provide a defect network construction of a fracton phase hosting non-Abelian fractons. As a byproduct of this construction, we obtain a generalized membrane-net description for fractonic ground states as well as an argument that our conjecture implies no topological fracton phases exist in 2+1-dimensional gapped systems. Our paper also sheds light on techniques for constructing higher-order gapped boundaries of 3+1D TQFTs.}, doi = {10.1103/PhysRevResearch.2.043165}, author = {Aasen, David and Bulmash, Daniel and Prem, Abhinav and Slagle, Kevin and Williamson, Dominic J.} } @article { ISI:000554826100006, title = {Topological superconductivity, ferromagnetism, and valley-polarized phases in moire systems: Renormalization group analysis for twisted double bilayer graphene}, journal = {Phys. Rev. B}, volume = {102}, number = {8}, year = {2020}, month = {AUG 3}, pages = {085103}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Recent experiments have observed possible spin- and valley-polarized insulators and spin-triplet superconductivity in twisted double bilayer graphene, a moire structure consisting of a pair of Bernal-stacked bilayer graphene. Besides the continuously tunable bandwidths controlled by an applied displacement field and twist angle, these moire bands also possess Van Hove singularities near the Fermi surface and a field-dependent nesting which is far from perfect. Here we carry out a perturbative renormalization group analysis to unbiasedly study the competition among all possible instabilities in twisted double bilayer graphene and related systems with a similar Van Hove fermiology in the presence of weak but finite repulsive interactions. Our key finding is that there are several competing magnetic, valley, charge, and superconducting instabilities arising from interactions in twisted double bilayer graphene, which can be tuned by controlling the displacement field and the twist angle. In particular, we show that spin- or valley-polarized uniform instabilities generically dominate under moderate interactions smaller than the bandwidth, whereas p-wave spin-triplet topological superconductivity and exotic spin-singlet modulated paired state become important as the interactions decrease. Realization of our findings in general moire systems with a similar Van Hove fermiology should open up new opportunities for manipulating topological superconductivity and spin- or valley-polarized states in highly tunable platforms.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.102.085103}, author = {Hsu, Yi-Ting and Wu, Fengcheng and Das Sarma, S.} } @article {16646, title = {Towards analog quantum simulations of lattice gauge theories with trapped ions}, journal = {Phys. Rev. Research}, volume = {2}, year = {2020}, month = {Apr}, pages = {023015}, doi = {10.1103/PhysRevResearch.2.023015}, url = {https://link.aps.org/doi/10.1103/PhysRevResearch.2.023015}, author = {Davoudi, Zohreh and Hafezi, Mohammad and Monroe, Christopher and Pagano, Guido and Seif, Alireza and Shaw, Andrew} } @article {vu_tunneling_2020, title = {Tunneling conductance of long-range {Coulomb} interacting {Luttinger} liquid}, journal = {Phys. Rev. Res.}, volume = {2}, number = {2}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {may}, abstract = {The theoretical model of the short-range interacting Luttinger liquid predicts a power-law scaling of the density of states and the momentum distribution function around the Fermi surface, which can be readily tested through tunneling experiments. However, some physical systems have long-range interaction, most notably the Coulomb interaction, leading to significantly different behaviors from the short-range interacting system. In this paper, we revisit the tunneling theory for the one-dimensional electrons interacting via the long-range Coulomb force. We show that, even though in a small dynamic range of temperature and bias voltage the tunneling conductance may appear to have a power-law decay similar to short-range interacting systems, the effective exponent is scale dependent and slowly increases with decreasing energy. This factor may lead to the sample-to-sample variation in the measured tunneling exponents. We also discuss the crossover to a free Fermi gas at high energy and the effect of the finite size. Our work demonstrates that experimental tunneling measurements in one-dimensional electron systems should be interpreted with great caution when the system is a Coulomb Luttinger liquid.}, doi = {10.1103/PhysRevResearch.2.023246}, author = {Vu, DinhDuy and Iucci, Anibal and Das Sarma, S.} } @article { ISI:000562002100002, title = {Two-dimensional electron self-energy: Long-range Coulomb interaction}, journal = {Phys. Rev. B}, volume = {102}, number = {8}, year = {2020}, month = {AUG 24}, pages = {085145}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {The electron self-energy for long-range Coulomb interactions plays a crucial role in understanding the many-body physics of interacting electron systems (e.g., in metals and semiconductors) and has been studied extensively for decades. In fact, it is among the oldest and the most-investigated many-body problems in physics. However, there is a lack of an analytical expression for the self-energy Re Sigma((R)) (epsilon, T) when energy epsilon and temperature k(B)T are arbitrary with respect to each other (while both being still small compared with the Fermi energy). We revisit this problem and calculate analytically the self-energy on the mass shell for a two-dimensional electron system with Coulomb interactions in the high density limit r(s)<< 1, for temperature r(s)(3/2) << k(B)T/E-F << r(s) and energy r(s)(3/2) << vertical bar epsilon vertical bar << r(s). We provide the exact high-density analytical expressions for the real and imaginary parts of the electron self-energy with arbitrary value of epsilon/KBT, to the leading order in the dimensionless Coulomb coupling constant r(s), and to several higher than leading orders in k(B)T/r(s)E(F) and epsilon/r(s)E(F) . We also obtain the asymptotic behavior of the self-energy in the regimes vertical bar epsilon vertical bar << k(B)T and vertical bar epsilon vertical bar >> k(B)T. The higher-order terms have subtle and highly nontrivial compound logarithmic contributions from both epsilon and T, explaining why they have never before been calculated in spite of the importance of the subject matter.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.102.085145}, author = {Liao, Yunxiang and Buterakos, Donovan and Schecter, Mike and Das Sarma, Sankar} } @article { ISI:000560967100009, title = {Unitary Subharmonic Response and Floquet Majorana Modes}, journal = {Phys. Rev. Lett.}, volume = {125}, number = {8}, year = {2020}, month = {AUG 20}, pages = {086804}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Detection and manipulation of excitations with non-Abelian statistics, such as Majorana fermions, are essential for creating topological quantum computers. To this end, we show the connection between the existence of such localized particles and the phenomenon of unitary subharmonic response (SR) in periodically driven systems. In particular, starting from highly nonequilibrium initial states, the unpaired Majorana modes exhibit spin oscillations with twice the driving period, are localized, and can have exponentially long lifetimes in clean systems. While the lifetime of SR is limited in translationally invariant systems, we show that disorder can be engineered to stabilize the subharmonic response of Majorana modes. A viable observation of this phenomenon can be achieved using modern multiqubit hardware, such as superconducting circuits and cold atomic systems.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.125.086804}, author = {Shtanko, Oles and Movassagh, Ramis} } @article {lu_universal_2020, title = {Universal frequency engineering tool for microcavity nonlinear optics: multiple selective mode splitting of whispering-gallery resonances}, journal = {Photonics Res.}, volume = {8}, number = {11}, year = {2020}, note = {Place: PO BOX 800-211, SHANGHAI, 201800, PEOPLES R CHINA Publisher: CHINESE LASER PRESS Type: Article}, month = {nov}, pages = {1676{\textendash}1686}, abstract = {Whispering-gallery microcavities have been used to realize a variety of efficient parametric nonlinear optical processes through the enhanced light-matter interaction brought about by supporting multiple high quality factor and small modal volume resonances. Critical to such studies is the ability to control the relative frequencies of the cavity modes, so that frequency matching is achieved to satisfy energy conservation. Typically this is done by tailoring the resonator cross section. Doing so modifies the frequencies of all of the cavity modes, that is, the global dispersion profile, which may be undesired, for example, in introducing competing nonlinear processes. Here, we demonstrate a frequency engineering tool, termed multiple selective mode splitting (MSMS), that is independent of the global dispersion and instead allows targeted and independent control of the frequencies of multiple cavity modes. In particular, we show controllable frequency shifts up to 0.8 nm, independent control of the splitting of up to five cavity modes with optical quality factors {\textgreater}= 10(5), and strongly suppressed frequency shifts for untargeted modes. The MSMS technique can be broadly applied to a wide variety of nonlinear optical processes across different material platforms and can be used to both selectively enhance processes of interest and suppress competing unwanted processes.}, issn = {2327-9125}, doi = {10.1364/PRJ.401755}, author = {Lu, Xiyuan and Rao, Ashutosh and Moille, Gregory and Westly, Daron A. and Srinivasan, Kartik} } @article { ISI:000501768100003, title = {Additive biomanufacturing of scaffolds for breast reconstruction}, journal = {Addit. Manuf.}, volume = {30}, year = {2019}, month = {DEC}, pages = {UNSP 100845}, publisher = {ELSEVIER}, type = {Article}, abstract = {Limitations for the current clinical treatment strategies for breast reconstruction have prompted researchers and bioengineers to develop unique techniques based on tissue engineering and regenerative medicine (TE\&RM) principles. Recently, scaffold-guided soft TE has emerged as a promising approach due to its potential to modulate the process of tissue regeneration. Herein, we utilized additive biomanufacturing (ABM) to develop an original design-based concept for scaffolds which can be applied in TE-based breast reconstruction procedures. The scaffold design addresses biomechanical and biological requirements for medium to large-volume regeneration with the potential of customization. The model is composed of two independent structural components. The external structure provides biomechanical stability to minimize load transduction to the newly formed tissue while the internal structure provides a large pore and fully interconnected pore architecture to facilitate tissue regeneration. A methodology was established to design, optimize and 3D print the external structure with customized biomechanical properties. The internal structure was also designed and printed with a gradient of pore size and a channel structure to facilitate lipoaspirated fat delivery and entrapment. A fused filament fabrication-based printing strategy was employed to print two structures as a monolithic breast implant.}, keywords = {Additive biomanufacturing, Breast implant customization, In silico modelling, Scaffolds}, issn = {2214-8604}, doi = {10.1016/j.addma.2019.100845}, author = {Mohseni, Mina and Bas, Onur and Castro, Nathan J. and Schmutz, Beat and Hutmacher, Dietmar W.} } @article {13366, title = {Alignment-dependent decay rate of an atomic dipole near an optical nanofiber}, journal = {Phys. Rev. A}, volume = {99}, year = {2019}, month = {Jan}, pages = {013822}, doi = {10.1103/PhysRevA.99.013822}, url = {https://link.aps.org/doi/10.1103/PhysRevA.99.013822}, author = {Solano, P. and Grover, J. A. and Xu, Y. and Barberis-Blostein, P. and Munday, J. N. and Orozco, L. A. and Phillips, W. D. and Rolston, S. L.} } @article { ISI:000454906800010, title = {Artificial gauge fields with ultracold atoms}, journal = {PHYSICS TODAY}, volume = {72}, number = {1}, year = {2019}, month = {JAN}, pages = {39-44}, issn = {0031-9228}, doi = {10.1063/PT.3.4111}, author = {Galitski, Victor and Juzeliunas, Gediminas and Ian B Spielman} } @conference {ISI:000482088000005, title = {Auger recombination-induced neutralization and stretched exponential recharging in an InAs quantum dot}, booktitle = {QUANTUM DOTS AND NANOSTRUCTURES: GROWTH, CHARACTERIZATION, AND MODELING XVI}, series = {Proceedings of SPIE}, volume = {10929}, year = {2019}, note = {Conference on Quantum Dots and Nanostructures: Growth, Characterization, and Modeling XVI, San Francisco, CA, FEB 06-07, 2019}, pages = {109290F}, publisher = {SPIE}, organization = {SPIE}, type = {Proceedings Paper}, abstract = {We investigate the charging dynamics in epitaxially grown InAs quantum dots (QDs) under resonant excitation with and without additional low-power above-band excitation. Time-resolved resonance fluorescence from a charged exciton (trion) transition is recorded as the above-band excitation is modulated on and off. The fluorescence intensity varies as the QD changes from charged to neutral and back due to the influence of the above-band excitation. We fit the transients of the decay of the time-resolved resonance fluorescence after the above-band excitation turns off with a model that represents the neutralization process. The time dependence of the transients indicate that Auger recombination of resonantly excited trions is largely responsible for neutralization of the charged state when the above-band excitation is off. Additionally, a stretched exponential component of the transient of the fluorescence decay indicates the QD is supplied with charges via carrier migration through a stochastic collection of weakly-binding sites, resulting in sub-diffusion-like dynamics.}, keywords = {anomalous diffusion, Auger recombination, charge carrier dynamics, quantum dot, resonance fluorescence, stretched exponential, time-resolved, trion}, isbn = {978-1-5106-2501-3}, issn = {0277-786X}, doi = {10.1117/12.2506555}, author = {Lander, Gary R. and Isaac, Samantha D. and Chen, Disheng and Demircan, Samet and Solomon, Glenn S. and Flagg, Edward B.}, editor = {Huffaker, DL and Eisele, H} } @article { ISI:000500475200001, title = {Benchmarking an 11-qubit quantum computer}, journal = {Nat. Commun.}, volume = {10}, year = {2019}, month = {NOV 29}, pages = {5464}, publisher = {NATURE PUBLISHING GROUP}, type = {Article}, abstract = {The field of quantum computing has grown from concept to demonstration devices over the past 20 years. Universal quantum computing offers efficiency in approaching problems of scientific and commercial interest, such as factoring large numbers, searching databases, simulating intractable models from quantum physics, and optimizing complex cost functions. Here, we present an 11-qubit fully-connected, programmable quantum computer in a trapped ion system composed of 13 Yb-171(+) ions. We demonstrate average single-qubit gate fidelities of 99.5\%, average two-qubit-gate fidelities of 97.5\%, and SPAM errors of 0.7\%. To illustrate the capabilities of this universal platform and provide a basis for comparison with similarly-sized devices, we compile the Bernstein-Vazirani and Hidden Shift algorithms into our native gates and execute them on the hardware with average success rates of 78\% and 35\%, respectively. These algorithms serve as excellent benchmarks for any type of quantum hardware, and show that our system outperforms all other currently available hardware.}, issn = {2041-1723}, doi = {10.1038/s41467-019-13534-2}, author = {Wright, K. and Beck, K. M. and Debnath, S. and Amini, J. M. and Nam, Y. and Grzesiak, N. and Chen, J. -S. and Pisenti, N. C. and Chmielewski, M. and Collins, C. and Hudek, K. M. and Mizrahi, J. and Wong-Campos, J. D. and Allen, S. and Apisdorf, J. and Solomon, P. and Williams, M. and Ducore, A. M. and Blinov, A. and Kreikemeier, S. M. and Chaplin, V. and Keesan, M. and Monroe, C. and Kim, J.} } @conference {ISI:000482226303019, title = {Bright Beams of Intensity Difference Squeezed Light for use in Sub-shot-noise Imaging}, booktitle = {2019 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO)}, series = {Conference on Lasers and Electro-Optics}, year = {2019}, note = {Conference on Lasers and Electro-Optics (CLEO), San Jose, CA, MAY 05-10, 2019}, publisher = {IEEE; AdValue Photon; Amer Elements; Class5 Photon; Coherent; GoFoton; Light Convers; LightTrans; MKS; OZ Opt Online; Santec; ThorLabs; UQDevices; YSL Photon}, organization = {IEEE; AdValue Photon; Amer Elements; Class5 Photon; Coherent; GoFoton; Light Convers; LightTrans; MKS; OZ Opt Online; Santec; ThorLabs; UQDevices; YSL Photon}, type = {Proceedings Paper}, abstract = {We present a method for using bright beams of intensity difference squeezed light to perform sub-shot-noise imaging. The intensity correlated twin beams are generated by four wave mixing in rubidium vapour. (C) 2019 The Author(s)}, isbn = {978-1-943580-57-6}, issn = {2160-9020}, author = {Speirs, Rory W. and Brewer, Nicholas R. and Wu, Meng-Chang and Lett, Paul D.} } @article { ISI:000488503500029, title = {Broadband resonator-waveguide coupling for efficient extraction of octave-spanning microcombs}, journal = {Opt. Lett.}, volume = {44}, number = {19}, year = {2019}, month = {OCT 1}, pages = {4737-4740}, publisher = {OPTICAL SOC AMER}, type = {Article}, abstract = {Octave-spanning frequency combs have been successfully demonstrated in Kerr nonlinear microresonators. These microcombs rely on both engineered dispersion, to enable generation of frequency components across the octave, and on engineered coupling, to efficiently extract the generated light into an access waveguide while maintaining a close to critically coupled pump. The latter is challenging, as the spatial overlap between the access waveguide and the ring modes decays with frequency. This leads to strong coupling variation across the octave, with poor extraction at short wavelengths. Here, we investigate how a waveguide wrapped around a portion of the resonator, in a pulley scheme, can improve the extraction of octave-spanning microcombs, in particular at short wavelengths. We use the coupled-mode theory to predict the performance of the pulley couplers and demonstrate good agreement with experimental measurements. Using an optimal pulley coupling design, we demonstrate a 20 dB improvement in extraction at short wavelengths compared to straight waveguide coupling. (C) 2019 Optical Society of America}, issn = {0146-9592}, doi = {10.1364/OL.44.004737}, author = {Moille, Gregory and Li, Qing and Briles, Travis C. and Yu, Su-Peng and Drake, Tara and Lu, Xiyuan and Rao, Ashutosh and Westly, Daron and Papp, Scott B. and Srinivasan, Kartik} } @article {ISI:000456301900009, title = {Conductance smearing and anisotropic suppression of induced superconductivity in a Majorana nanowire}, journal = {Phys. Rev. B}, volume = {99}, number = {2}, year = {2019}, month = {JAN 22}, pages = {024510}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {In a recent high-quality experimental work on normal metal-superconducting nanowire junctions (J. D. S. Bommer et al., arXiv :1807.01940), strong anisotropic suppression of induced superconductivity has been observed in tunnel conductance measurements in the presence of applied magnetic field with variable orientation. Following this finding, we investigate theoretically the dependence of tunnel conductance on the direction of the Zeeman field in order to understand the operational mechanisms and to extract effective system parameters. Second, motivated by a generic discrepancy between experiment and theory, i.e., many in-gap and above-gap conductance features predicted by theory are barely observed in experiments, we study several mechanisms possibly responsible for the suppression of the theoretically predicted conductance features (e.g., length of the nanowire, self-energy effect due to the proximity effect, finite temperature, finite dissipation, and multiband effect). One essential finding in the current work is that only by a combined understanding of both suppression mechanisms can we extract effective system parameters from the experimental data (e.g., the effective nanowire-superconductor coupling, the effective Lande g factor, and the chemical potential of the semiconducting nanowire). In addition, we consider topologically trivial Andreev bound states in hybrid nanowires in the presence of potential inhomogeneities, such as external quantum dots or potential inhomogeneities inside the nanowire. We compare the anisotropic, field-dependent features induced by these nontopological Andreev bound states with the corresponding features produced by topological Majorana zero modes in pristine nanostructures, so that we can provide guidance to differentiate between the topologically trivial and nontrivial cases.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.99.024510}, author = {Liu, Chun-Xiao and Sau, Jay D. and Stanescu, Tudor D. and S. Das Sarma} } @article { ISI:000504862300005, title = {Coupled electron-impurity and electron-phonon systems as trivial non-Fermi liquids}, journal = {Phys. Rev. B}, volume = {100}, number = {23}, year = {2019}, month = {DEC 30}, pages = {235149}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We consider an electron gas, both in two (2D) and three (3D) dimensions, interacting with quenched impurities and phonons within leading order finite-temperature many-body perturbation theories, calculating the electron self-energies, spectral functions, and momentum distribution functions at finite temperatures. The resultant spectral function is in general highly non-Lorentzian, indicating that the system is not a Fermi liquid in the usual sense. The calculated momentum distribution function cannot be approximated by a Fermi function at any temperature, providing a rather simple example of a non-Fermi liquid with well-understood properties.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.100.235149}, author = {Buterakos, Donovan and Das Sarma, Sankar} } @article {ISI:000458854900004, title = {Curvature of gap closing features and the extraction of Majorana nanowire parameters}, journal = {Phys. Rev. B}, volume = {99}, number = {5}, year = {2019}, month = {FEB 15}, pages = {054507}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Recent tunneling conductance measurements of Majorana nanowires show a strong variation in the magnetic-field dependence of the superconducting gap among different devices. Here, we theoretically study the magnetic field dependence of the gap closing feature and establish that the degree of convexity (or concavity) of the gap closing as a function of Zeeman field can provide critical constraints on the underlying microscopic parameters of the semiconductor-superconductor hybrid system model. Specifically, we show that the gap closing feature is entirely concave only for strong spin-orbit coupling strength relative to the chemical potential. Additionally, the nonlinearity (i.e., concavity or convexity) of the gap closing as a function of magnetic field complicates the simple assignment of a constant effective g-factor to the states in the Majorana nanowire. We develop a procedure to estimate the effective g-factor from recent experimental data that accounts for the nonlinear gap closing, resulting from the interplay between chemical potential and spin-orbit coupling. Thus, measurements of the magnetic field dependence of the gap closure on the trivial side of the topological quantum phase transition can provide useful information on parameters that are critical to the theoretical modeling of Majorana nanowires.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.99.054507}, author = {Pan, Haining and Sau, Jay D. and Stanescu, Tudor D. and S. Das Sarma} } @article { ISI:000491132700014, title = {Demonstration of slow light in rubidium vapor using single photons from a trapped ion}, journal = {Sci. Adv.}, volume = {5}, number = {10}, year = {2019}, month = {OCT}, pages = {eaav4651}, publisher = {AMER ASSOC ADVANCEMENT SCIENCE}, type = {Article}, abstract = {Practical implementation of quantum networks is likely to interface different types of quantum systems. Photonically linked hybrid systems, combining unique properties of each constituent system, have typically required sources with the same photon emission wavelength. Trapped ions and neutral atoms both have compelling properties as nodes and memories in a quantum network but have never been photonically linked because of vastly different operating wavelengths. Here, we demonstrate the first interaction between neutral atoms and photons emitted from a single trapped ion. We use slow light in Rb-87 vapor to delay photons originating from a trapped Ba-138(+) ion by up to 13.5 +/- 0.5 ns, using quantum frequency conversion to overcome the frequency difference between the ion and neutral atoms. The delay is tunable and preserves the temporal profile of the photons. This result showcases a hybrid photonic interface usable as a synchronization tool-a critical component in any future large-scale quantum network.}, issn = {2375-2548}, doi = {10.1126/sciadv.aav4651}, author = {Siverns, J. D. and Hannegan, J. and Quraishi, Q.} } @article {ISI:000461830900002, title = {Development of transmon qubits solely from optical lithography on 300 mm wafers}, journal = {Quantum Sci. Technol.}, volume = {4}, number = {2}, year = {2019}, month = {APR}, pages = {025012}, publisher = {IOP PUBLISHING LTD}, type = {Article}, abstract = {Qubit information processors are increasing in footprint but currently rely on e-beam lithography for patterning the required Josephson junctions (JJs). Advanced optical lithography is an alternative patterning method, and we report on the development of transmon qubits patterned solely with optical lithography. The lithography uses 193 nm wavelength exposure and 300 mm large silicon wafers. Qubits and arrays of evaluation JJs were patterned with process control which resulted in narrow feature distributions: a standard deviation of 0.78\% for a 220 nm linewidth pattern realized across over half the width of the wafers. Room temperature evaluation found a 2.8\%-3.6\% standard deviation in JJ resistance in completed chips. The qubits used aluminum and titanium nitride films on silicon substrates without substantial silicon etching. T-1 times of the qubits were extracted at 26-27 mu s, indicating a low level of material-based qubit defects. This study shows that large wafer optical lithography on silicon is adequate for high-quality transmon qubits, and shows a promising path for improving many-qubit processors.}, keywords = {fabrication, large wafer, QUBIT, silicon, superconducting}, issn = {2058-9565}, doi = {10.1088/2058-9565/ab0ca8}, author = {Foroozani, N. and Hobbs, C. and Hung, C. C. and Olson, S. and Ashworth, D. and Holland, E. and Malloy, M. and Kearney, P. and O{\textquoteright}Brien, B. and Bunday, B. and DiPaola, D. and Advocate, W. and Murray, T. and Hansen, P. and Novak, S. and Bennett, S. and Rodgers, M. and Baker-O{\textquoteright}Neal, B. and Sapp, B. and Barth, E. and Hedrick, J. and Goldblatt, R. and Rao, S. S. Papa and Osborn, K. D.} } @article {ISI:000475496800004, title = {Diabatic errors in Majorana braiding with bosonic bath}, journal = {Phys. Rev. B}, volume = {100}, number = {1}, year = {2019}, month = {JUL 12}, pages = {014511}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Majorana mode based topological qubits are potentially subject to diabatic errors that in principle can limit the utility of topological quantum computation. Using a combination of analytical and numerical methods we study the diabatic errors in Majorana-based topological Y junction that are coupled to a Bosonic bath in the Markovian approximation. We find that in the absence of a bath, the error can be made exponentially small with increasing braiding time, only when the time variation in the Hamiltonian is completely smooth. The presence of a dominantly dissipative Markovian bath is found to eliminate this exponential scaling of error to a power-law scaling as T-1 with T being the braiding time. However, the inclusion of relaxation improves this scaling slightly to go as T-2. Thus, coupling of topological systems to Bosonic baths can lead to power law in braiding time diabatic errors that might limit the speed of topologically protected operations using Majorana modes.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.100.014511}, author = {Nag, Amit and Sau, Jay D.} } @article {ISI:000455814100005, title = {Dynamic polarizability measurements with Lu-176(+)}, journal = {Phys. Rev. A}, volume = {99}, number = {1}, year = {2019}, month = {JAN 15}, pages = {012510}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We measure the differential polarizability of the Lu-176(+) S-1(0) <-> D-3(1) clock transition at multiple wavelengths. This experimentally characterizes the differential dynamic polarizability for frequencies up to 372 THz and allows an experimental determination of the dynamic correction to the blackbody radiation shift for the clock transition. In addition, measurements at the near resonant wavelengths of 598 and 646 nm determine the two dominant contributions to the differential dynamic polarizability below 372 THz. These additional measurements are carried out by two independent methods to verify the validity of our methodology. We also carry out a theoretical calculation of the polarizabilities using the hybrid method that combines the configuration interaction (CI) and the coupled-cluster approaches, incorporating for the first time quadratic nonlinear terms and partial triple excitations in the coupled-cluster calculations. The experimental measurements of the vertical bar < D-3(1)parallel to r parallel to P-3(J)>vertical bar matrix elements provide high-precision benchmarks for this theoretical approach.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.99.012510}, author = {Arnold, K. J. and Kaewuam, R. and Tan, T. R. and Porsev, S. G. and Safronova, M. S. and Barrett, M. D.} } @article {ISI:000466037000001, title = {Dynamical Hamiltonian engineering of 2D rectangular lattices in a one-dimensional ion chain}, journal = {npj Quantum Inform.}, volume = {5}, year = {2019}, month = {APR 26}, pages = {32}, publisher = {SPRINGERNATURE}, type = {Article}, abstract = {Controlling the interaction graph between spins or qubits in a quantum simulator allows user-controlled tailoring of native interactions to achieve a target Hamiltonian. Engineering long-ranged phonon-mediated spin-spin interactions in a trapped ion quantum simulator offers such a possibility. Trapped ions, a leading candidate for quantum simulation, are most readily trapped in a linear 1D chain, limiting their utility for readily simulating higher dimensional spin models. In this work, we introduce a hybrid method of analog-digital simulation for simulating 2D spin models which allows for the dynamic changing of interactions to achieve a new graph using a linear 1D chain. We focus this numerical work on engineering 2D rectangular nearest-neighbor spin lattices, demonstrating that the required control parameters scale linearly with ion number. This hybrid approach offers compelling possibilities for the use of 1D chains in the study of Hamiltonian quenches, dynamical phase transitions, and quantum transport in 2D and 3D.}, doi = {10.1038/s41534-019-0147-x}, author = {Rajabi, Fereshteh and Motlakunta, Sainath and Shih, Chung-You and Kotibhaskar, Nikhil and Quraishi, Qudsia and Ajoy, Ashok and Islam, Rajibul} } @article { ISI:000505563100013, title = {Dynamics of analog logic-gate networks for machine learning}, journal = {Chaos}, volume = {29}, number = {12}, year = {2019}, month = {DEC}, pages = {123130}, publisher = {AMER INST PHYSICS}, type = {Article}, abstract = {We describe the continuous-time dynamics of networks implemented on Field Programable Gate Arrays (FPGAs). The networks can perform Boolean operations when the FPGA is in the clocked (digital) mode; however, we run the programed FPGA in the unclocked (analog) mode. Our motivation is to use these FPGA networks as ultrafast machine-learning processors, using the technique of reservoir computing. We study both the undriven dynamics and the input response of these networks as we vary network design parameters, and we relate the dynamics to accuracy on two machine-learning tasks. Published under license by AIP Publishing.}, issn = {1054-1500}, doi = {10.1063/1.5123753}, author = {Shani, Itamar and Shaughnessy, Liam and Rzasa, John and Restelli, Alessandro and Hunt, Brian R. and Komkov, Heidi and Lathrop, Daniel P.} } @article {ISI:000483304200006, title = {Efficient telecom-to-visible spectral translation through ultralow power nonlinear nanophotonics}, journal = {Nat. Photonics}, volume = {13}, number = {9}, year = {2019}, month = {SEP}, pages = {593+}, publisher = {NATURE PUBLISHING GROUP}, type = {Article}, abstract = {The ability to spectrally translate lightwave signals in a compact, low-power platform is at the heart of the promise of nonlinear nanophotonic technologies. For example, a device to connect the telecommunications band with visible and short near-infrared wavelengths can enable a connection between high-performance chip-integrated lasers based on scalable nanofabrication technology with atomic systems used for time and frequency metrology. Although second-order nonlinear (chi((2))) systems are the natural approach for bridging such large spectral gaps, here we show that third-order nonlinear (chi((3))) systems, despite their typically much weaker nonlinear response, can realize spectral translation with unprecedented performance. By combining resonant enhancement with nanophotonic mode engineering in a silicon nitride microring resonator, we demonstrate efficient spectral translation of a continuous-wave signal from the telecom band (similar to 1,550 nm) to the visible band (similar to 650 nm) through cavity-enhanced four-wave mixing. We achieve such translation over a wide spectral range >250 THz with a translation efficiency of (30.1 +/- 2.8)\% and using an ultralow pump power of (329 +/- 13) mu W. The translation efficiency projects to (274 +/- 28)\% at 1 mW and is more than an order of magnitude larger than what has been achieved in current nanophotonic devices.}, issn = {1749-4885}, doi = {10.1038/s41566-019-0464-9}, author = {Lu, Xiyuan and Moille, Gregory and Li, Qing and Westlyl, Daron A. and Singh, Anshuman and Rao, Ashutosh and Yu, Su-Peng and Briles, Travis C. and Papp, Scott B. and Srinivasan, Kartik} } @article {ISI:000466237600004, title = {Elastic rate coefficients for Li+H-2 collisions in the calibration of a cold-atom vacuum standard}, journal = {Phys. Rev. A}, volume = {99}, number = {4}, year = {2019}, month = {APR 29}, pages = {042704}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Ongoing efforts at the National Institute of Standards and Technology in creating a cold-atom vacuum standard device have prompted theoretical investigations of atom-molecule collision processes that characterize its operation. Such a device will operate as a primary standard for the ultrahigh-vacuum and extreme-high-vacuum regimes. This device operates by relating loss of ultracold lithium atoms from a conservative trap by collisions with ambient atoms and molecules to the background density and thus pressure through the ideal gas law. The predominant background constituent in these environments is molecular hydrogen H-2. We compute the relevant Li+H-2 Born-Oppenheimer potential energy surface, paying special attention to its uncertainty. Coupled-channel calculations are then used to obtain total rate coefficients, which include momentum-changing elastic and inelastic processes. We find that inelastic rotational quenching of H-2 is negligible near room temperature. For a (T = 300)-K gas of H-2 and 1.0-mu K gas of Li atoms prepared in a single hyperfine state, the total rate coefficients are 6.0(1) x 10(-9) cm(3)/s for both Li-6 and Li-7 isotopes, where the number in parentheses corresponds to a one-standard-deviation combined statistical and systematic uncertainty. We find that a 10-K increase in the H-2 temperature leads to a 1.9\% increase in the rate coefficients for both isotopes. For Li temperatures up to 100 mu K, changes are negligible. Finally, a semiclassical Born approximation significantly overestimates the rate coefficients. The difference is at least ten times the uncertainty of the coupled-channel result.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.99.042704}, author = {Makrides, Constantinos and Barker, Daniel S. and Fedchak, James A. and Scherschligt, Julia and Eckel, Stephen and Tiesinga, Eite} } @article {ISI:000460648100005, title = {Electric dipole matrix elements for the 6p(2)P(J) -> 7s(2)S(1/2) transition in atomic cesium}, journal = {Phys. Rev. A}, volume = {99}, number = {3}, year = {2019}, month = {MAR 5}, pages = {032504}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We report a measurement of the ratio of electric dipole transition matrix elements of cesium for the 6p(2)P(1/2) -> 7s(2)S(1/2) and 6p(2)P(3/2) -> 7s(2)S(1/2 )transitions. We determine this ratio of matrix elements through comparisons of two-color, two-photon excitation rates of the 7s(2)S(1/2) state using laser beams with polarizations parallel to one another vs perpendicular to one another. Our result of R < 7s(2)S(1/2)parallel to r parallel to 6P(2)P(3/2)>/< 7s(2)S(1/2)parallel to r parallel to 6P(2)P(1/2)> = 1.5272(17) is in excellent agreement with a theoretical prediction of R = 1.5270(27). Moreover, the accuracy of the experimental ratio is sufficiently high to differentiate between various theoretical approaches. To our knowledge, there are no prior experimental measurements of R. Combined with our recent determination of the lifetime of the 7s(2)S(1/2) state, we determine reduced matrix elements for these two transitions, < 7s(2)S(1/2)parallel to r parallel to 6P(2)P(3/2)> = -6.489(5)a(0) and < 7s(2)S(1/2)parallel to r parallel to 6P(2)P(1/2 >) = -4.249(4)a(0). These matrix elements are also in excellent agreement with theoretical calculations. These measurements improve knowledge of Cs properties needed for parity violation studies and provide benchmarks for tests of high-precision theory.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.99.032504}, author = {Toh, George and Damitz, Amy and Glotzbach, Nathan and Quirk, Jonah and Stevenson, I. C. and Choi, J. and Safronova, M. S. and Elliott, D. S.} } @article {ISI:000466405300001, title = {Electronic structure of full-shell InAs/Al hybrid semiconductor-superconductor nanowires: Spin-orbit coupling and topological phase space}, journal = {Phys. Rev. B}, volume = {99}, number = {16}, year = {2019}, month = {APR 26}, pages = {161118}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We study the electronic structure of full-shell superconductor-semiconductor nanowires, which have recently been proposed for creating Majorana zero modes, using an eight-band (k) over right arrow . (p) over right arrow model within a fully self-consistent Schrodinger-Poisson scheme. We find that the spin-orbit coupling induced by the intrinsic radial electric field is generically weak for subbands with their minimum near the Fermi energy. Furthermore, we show that the chemical potential windows consistent with the emergence of a topological phase are small and sparse and can only be reached by fine-tuning the diameter of the wire. These findings suggest that the parameter space consistent with the realization of a topological phase in full-shell InAs/Al nanowires is, at best, very narrow.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.99.161118}, author = {Woods, Benjamin D. and S. Das Sarma and Stanescu, Tudor D.} } @article {ISI:000468026100013, title = {Emergent gauge field and the Lifshitz transition of spin-orbit coupled bosons in one dimension}, journal = {Sci Rep}, volume = {9}, year = {2019}, month = {MAY 16}, pages = {7471}, publisher = {NATURE PUBLISHING GROUP}, type = {Article}, abstract = {In the presence of strong spin-independent interactions and spin-orbit coupling, we show that the spinor Bose liquid confined to one spatial dimension undergoes an interaction-or density-tuned quantum phase transition similar to one theoretically proposed for itinerant magnetic solid-state systems. The order parameter describes broken Z2 inversion symmetry, with the ordered phase accompanied by non-vanishing momentum which is generated by fluctuations of an emergent dynamical gauge field at the phase transition. This quantum phase transition has dynamical critical exponent z similar or equal to 2, typical of a Lifshitz transition, but is described by a nontrivial interacting fixed point. From direct numerical simulation of the microscopic model, we extract previously unknown critical exponents for this fixed point. Our model describes a realistic situation of 1D ultracold atoms with Raman-induced spin-orbit coupling, establishing this system as a platform for studying exotic critical behavior of the Hertz-Millis type.}, issn = {2045-2322}, doi = {10.1038/s41598-019-43929-6}, author = {Cole, William S. and Lee, Junhyun and Mahmud, Khan W. and Alavirad, Yahya and Spielman, I. B. and Sau, Jay D.} } @article {ISI:000473271300044, title = {Evolution of large-scale flow from turbulence in a two-dimensional superfluid}, journal = {Science}, volume = {364}, number = {6447}, year = {2019}, month = {JUN 28}, pages = {1267+}, publisher = {AMER ASSOC ADVANCEMENT SCIENCE}, type = {Article}, abstract = {Nonequilibrium interacting systems can evolve to exhibit large-scale structure and order. In two-dimensional turbulent flow, the seemingly random swirling motion of a fluid can evolve toward persistent large-scale vortices. To explain such behavior, Lars Onsager proposed a statistical hydrodynamic model based on quantized vortices. Here, we report on the experimental confirmation of Onsager{\textquoteright}s model. We dragged a grid barrier through an oblate superfluid Bose-Einstein condensate to generate nonequilibrium distributions of vortices. We observed signatures of an inverse energy cascade driven by the evaporative heating of vortices, leading to steady-state configurations characterized by negative absolute temperatures. Our results open a pathway for quantitative studies of emergent structures in interacting quantum systems driven far from equilibrium.}, issn = {0036-8075}, doi = {10.1126/science.aat5793}, author = {Johnstone, Shaun P. and Groszek, Andrew J. and Starkey, Philip T. and Billington, Christopher J. and Simula, Tapio P. and Helmerson, Kristian} } @article { ISI:000504435500005, title = {Ferromagnetism in quantum dot plaquettes}, journal = {Phys. Rev. B}, volume = {100}, number = {22}, year = {2019}, month = {DEC 23}, pages = {224421}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Following recent experimental progress concerning Nagaoka ferromagnetism in finite-size quantum dot plaquettes, a general theoretical analysis is warranted in order to ascertain in rather generic terms which arrangements of a small number of quantum dots can produce saturated ferromagnetic ground states and under which constraints on interaction and interdot tunneling in the plaquette. This is particularly necessary since Nagaoka ferromagnetism is fragile and arises only under rather special conditions. We test the robustness of ground state ferromagnetism in the presence of a long-range Coulomb interaction and long-range as well as short-range interdot hopping by modeling a wide range of different plaquette geometries accessible by arranging a few (similar to 4) quantum dots in a controlled manner. We find that ferromagnetism is robust to the presence of long-range Coulomb interactions, and we develop conditions constraining the tunneling strength such that the ground state is ferromagnetic. Additionally, we predict the presence of a partially spin-polarized ferromagnetic state for 4 electrons in a Y-shaped 4-quantum-dot plaquette. Finally, we consider 4 electrons in a ring of 5 dots. This does not satisfy the Nagaoka condition; however, we show that the ground state is spin 1 for strong, but not infinite, on-site interaction. Thus, even though Nagaoka{\textquoteright}s theorem does not apply, the ground state for the finite system with one hole in a ring of 5 dots is partially ferromagnetic. We provide detailed fully analytical results for the existence or not of ferromagnetic ground states in several quantum dot geometries which can be studied in currently available coupled quantum dot systems.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.100.224421}, author = {Buterakos, Donovan and Das Sarma, Sankar} } @article {14546, title = {Fluctuation-Induced Torque on a Topological Insulator out of Thermal Equilibrium}, journal = {Phys. Rev. Lett.}, volume = {123}, year = {2019}, month = {Aug}, pages = {055901}, doi = {10.1103/PhysRevLett.123.055901}, url = {https://link.aps.org/doi/10.1103/PhysRevLett.123.055901}, author = {Maghrebi, M. F. and Gorshkov, A. V. and Sau, J. D.} } @article {ISI:000482940400006, title = {Frequency shifts due to Stark effects on a rubidium two-photon transition}, journal = {Phys. Rev. A}, volume = {100}, number = {2}, year = {2019}, month = {AUG 28}, pages = {023417}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {The 5S(1/2) -> 5D(5/2) two-photon transition in Rb is of interest for the development of a compact optical atomic clock. Here we present a rigorous calculation of the 778.1-nm ac Stark shift {[}2.30(4) x 10(-13)(mW/mm(2))(-1)] that is in good agreement with our measured value of 2.5(2) x 10(-13)(mW/mm(2))(-1). We include a calculation of the temperature-dependent blackbody radiation (BBR) shift, and we predict that the clock could be operated either with zero net BBR shift {[}T = 495.9(27) K] or with zero first-order sensitivity {[}T = 368.1(14) K]. Also described is the calculation of the dc Stark shift of 5.5(1) x 10(-15)/(V/cm(2)) as well as clock sensitivities to optical alignment variations in both a cat{\textquoteright}s eye and a flat mirror retroreflector. Finally, we characterize these Stark effects, discussing mitigation techniques necessary to reduce final clock instabilities.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.100.023417}, author = {Martin, Kyle W. and Stuhl, Benjamin and Eugenio, Jon and Safronova, Marianna S. and Phelps, Gretchen and Burke, John H. and Lemke, Nathan D.} } @article {14901, title = {Generation and detection of spin-orbit coupled neutron beams}, journal = {Proceedings of the National Academy of Sciences}, volume = {116}, year = {2019}, pages = {20328{\textendash}20332}, abstract = {Extensive interest has been placed on the techniques to prepare and characterize optical and matter wave orbital angular momentum (OAM) beams and spin correlated OAM beams. They have been shown to be useful in a wide range of applications such as microscopy, quantum information processing, material characterization, and communication protocols. Here we demonstrate an observation of spin-orbit beams and lattices of spin-orbit beams with neutrons. Neutrons, which do not possess a charge and have significant mass, are probes of nature that are complementary to photons and electrons. The techniques shown here enable neutron OAM applications in material characterization and fundamental physics.Spin-orbit coupling of light has come to the fore in nanooptics and plasmonics, and is a key ingredient of topological photonics and chiral quantum optics. We demonstrate a basic tool for incorporating analogous effects into neutron optics: the generation and detection of neutron beams with coupled spin and orbital angular momentum. The 3He neutron spin filters are used in conjunction with specifically oriented triangular coils to prepare neutron beams with lattices of spin-orbit correlations, as demonstrated by their spin-dependent intensity profiles. These correlations can be tailored to particular applications, such as neutron studies of topological materials.

}, issn = {0027-8424}, doi = {10.1073/pnas.1906861116}, url = {https://www.pnas.org/content/116/41/20328}, author = {Sarenac, Dusan and Kapahi, Connor and Chen, Wangchun and Clark, Charles W. and Cory, David G. and Huber, Michael G. and Taminiau, Ivar and Zhernenkov, Kirill and Pushin, Dmitry A.} } @article {ISI:000471944200018, title = {Griffiths physics in an ultracold Bose gas}, journal = {Phys. Rev. A}, volume = {99}, number = {6}, year = {2019}, month = {JUN 17}, pages = {063611}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Coupled XY model systems consisting of three-dimensional (3D) systems with disordered interlayer physics are of significant theoretical interest. We realize a set of coupled quasi-2D layers of Rb-87 in the presence of disordered interlayer coupling. This is achieved with our high bandwidth arbitrary optical lattice to obviate restrictions on the dimensionality of disorder with speckle-generated optical fields. We identify phase crossover regions compatible with the existence of a pair of intermediate Griffiths phases between a thermal state and the emergence of bulk 3D superfluidity.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.99.063611}, author = {Reed, M. E. W. and Smith, Z. S. and Dewan, Aftaab and Rolston, S. L.} } @article { ISI:000488282800085, title = {High purity single photons entangled with an atomic qubit}, journal = {Opt. Express}, volume = {27}, number = {20}, year = {2019}, month = {SEP 30}, pages = {28143-28149}, publisher = {OPTICAL SOC AMER}, type = {Article}, abstract = {Trapped atomic ions are an ideal candidate for quantum network nodes, with long-lived identical qubit memories that can be locally entangled through their Coulomb interaction and remotely entangled through photonic channels. The integrity of this photonic interface is generally reliant on the purity of single photons produced by the quantum memory. Here, we demonstrate a single-photon source for quantum networking based on a trapped Ba-138(+) ion with a single photon purity of g((2))(0) = (8.1 +/- 2.3) x 10(-5) without background subtraction. We further optimize the tradeoff between the photonic generation rate and the memory-photon entanglement fidelity for the case of polarization photonic qubits by tailoring the spatial mode of the collected light. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement}, issn = {1094-4087}, doi = {10.1364/OE.27.028143}, author = {Crocker, C. and Lichtman, M. and Sosnova, K. and Carter, A. and Scarano, S. and Monroe, C.} } @article { ISI:000498883600001, title = {High-Coherence Fluxonium Qubit}, journal = {Phys. Rev. X}, volume = {9}, number = {4}, year = {2019}, month = {NOV 25}, pages = {041041}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We report superconducting fluxonium qubits with coherence times largely limited by energy relaxation and reproducibly satisfying T-2 > 100 mu s (T-2 > 400 mu s in one device). Moreover, given the state-of-the-art values of the surface loss tangent and the 1/f flux-noise amplitude, the coherence time can be further improved beyond 1 ms. Our results violate a common viewpoint that the number of Josephson junctions in a superconducting circuit-over 10(2) here-must be minimized for best qubit coherence. We outline how the unique to fluxonium combination of long coherence time and large anharmonicity can benefit both gate-based and adiabatic quantum computing.}, issn = {2160-3308}, doi = {10.1103/PhysRevX.9.041041}, author = {Nguyen, Long B. and Lin, Yen-Hsiang and Somoroff, Aaron and Mencia, Raymond and Grabon, Nicholas and Manucharyan, Vladimir E.} } @article { ISI:000496923500007, title = {High-precision measurement and ab initio calculation of the (6s(2)6p(2)) P-3(0) -> P-3(2) electric-quadrupole-transition amplitude in Pb-208}, journal = {Phys. Rev. A}, volume = {100}, number = {5}, year = {2019}, month = {NOV 18}, pages = {052506}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We have completed a measurement of the (6s(2)6p(2)) P-3(0) -> P-3(2) 939 nm electric quadrupole (E2) transition amplitude in atomic lead. Using a Faraday rotation spectroscopy technique and a sensitive polarimeter, we have measured this very weak E2 transition, and determined its amplitude to be < P-3(2) parallel to Q parallel to P-3(0)> = 8.91(9) a.u. We also present an ab initio theoretical calculation of this matrix element, determining its value to be 8.86(5) a.u., which is in excellent agreement with the experimental result. We heat a quartz vapor cell containing Pb-208 to between 800 and 940 degrees C, apply a similar to 10 G longitudinal magnetic field, and use polarization modulation and lock-in detection to measure optical rotation amplitudes of order 1 mrad with noise near 1 mu rad. We compare the Faraday rotation amplitude of the E2 transition to that of the P-3(0)-P-3(1) 1279 nm magnetic dipole (M1) transition under identical sample conditions.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.100.052506}, author = {Maser, Daniel L. and Hoenig, Eli and Wang, B-Y and Rupasinghe, P. M. and Porsev, S. G. and Safronova, M. S. and Majumder, P. K.} } @article { ISI:000493335100001, title = {Identification of advanced spin-driven thermoelectric materials via interpretable machine learning}, journal = {npj Comput. Mater.}, volume = {5}, year = {2019}, month = {OCT 30}, pages = {103}, publisher = {SPRINGERNATURE}, type = {Article}, abstract = {Machine learning is becoming a valuable tool for scientific discovery. Particularly attractive is the application of machine learning methods to the field of materials development, which enables innovations by discovering new and better functional materials. To apply machine learning to actual materials development, close collaboration between scientists and machine learning tools is necessary. However, such collaboration has been so far impeded by the black box nature of many machine learning algorithms. It is often difficult for scientists to interpret the data-driven models from the viewpoint of material science and physics. Here, we demonstrate the development of spin-driven thermoelectric materials with anomalous Nernst effect by using an interpretable machine learning method called factorized asymptotic Bayesian inference hierarchical mixture of experts (FAB/HMEs). Based on prior knowledge of material science and physics, we were able to extract from the interpretable machine learning some surprising correlations and new knowledge about spin-driven thermoelectric materials. Guided by this, we carried out an actual material synthesis that led to the identification of a novel spin-driven thermoelectric material. This material shows the largest thermopower to date.}, issn = {2057-3960}, doi = {10.1038/s41524-019-0241-9}, author = {Iwasaki, Yuma and Sawada, Ryohto and Stanev, Valentin and Ishida, Masahiko and Kirihara, Akihiro and Omori, Yasutomo and Someya, Hiroko and Takeuchi, Ichiro and Saitoh, Eiji and Yorozu, Shinichi} } @article {ISI:000467473500012, title = {Imaging topology of Hofstadter ribbons}, journal = {New J. Phys.}, volume = {21}, year = {2019}, month = {MAY 8}, pages = {053021}, publisher = {IOP PUBLISHING LTD}, type = {Article}, abstract = {Physical systems with non-trivial topological order find direct applications in metrology (Klitzing et al 1980 Phys. Rev. Lett. 45 494-7) and promise future applications in quantum computing (Freedman 2001 Found. Comput. Math. 1 183-204; Kitaev 2003 Ann. Phys. 303 2-30). The quantum Hall effect derives from transverse conductance, quantized to unprecedented precision in accordance with the system{\textquoteright}s topology (Laughlin 1981 Phys. Rev. B 23 5632-33). At magnetic fields beyond the reach of current condensed matter experiment, around 10(4)T, this conductance remains precisely quantized with values based on the topological order (Thouless et al 1982 Phys. Rev. Lett. 49 405-8). Hitherto, quantized conductance has only been measured in extended 2D systems. Here, we experimentally studied narrow 2D ribbons, just 3 or 5 sites wide along one direction, using ultracold neutral atoms where such large magnetic fields can be engineered (Jaksch and Zoller 2003 New J. Phys. 5 56; Miyake et al 2013 Phys. Rev. Lett. 111 185302; Aidelsburger et al 2013 Phys. Rev. Lett. 111 185301; Celi et al 2014 Phys. Rev. Lett. 112 043001; Stuhl et al 2015 Science 349 1514; Mancini et al 2015 Science 349 1510; An et al 2017 Sci. Adv. 3). We microscopically imaged the transverse spatial motion underlying the quantized Hall effect. Our measurements identify the topological Chern numbers with typical uncertainty of 5\%, and show that although band topology is only properly defined in infinite systems, its signatures are striking even in nearly vanishingly thin systems.}, keywords = {quantum Hall effect, quantum simulation, quantum transport, ultracold atoms}, issn = {1367-2630}, doi = {10.1088/1367-2630/ab165b}, author = {Genkina, Dina and Aycock, Lauren M. and Lu, I, Hsin- and Lu, Mingwu and Pineiro, Alina M. and Spielman, I. B.} } @article { ISI:000490353500059, title = {Indistinguishable Photons from Deterministically Integrated Single Quantum Dots in Heterogeneous GaAs/Si3N4 Quantum Photonic Circuits}, journal = {Nano Lett.}, volume = {19}, number = {10}, year = {2019}, month = {OCT}, pages = {7164-7172}, publisher = {AMER CHEMICAL SOC}, type = {Article}, abstract = {Silicon photonics enables scaling of quantum photonic systems by allowing the creation of extensive, low-loss, reconfigurable networks linking various functional on-chip elements. Inclusion of single quantum emitters onto photonic circuits, acting as on-demand sources of indistinguishable photons or single-photon nonlinearities, may enable large-scale chip-based quantum photonic circuits and networks. Toward this, we use low-temperature in situ electron-beam lithography to deterministically produce hybrid GaAs/Si3N4 photonic devices containing single InAs quantum dots precisely located inside nanophotonic structures, which act as efficient, Si3N4 waveguide-coupled on-chip, on-demand single-photon sources. The precise positioning afforded by our scalable fabrication method furthermore allows observation of postselected indistinguishable photons. This indicates a promising path toward significant scaling of chip-based quantum photonics, enabled by large fluxes of indistinguishable single-photons produced on-demand, directly on-chip.}, keywords = {deterministic sample fabrication, hybrid devices, indistinguishable photons, Quantum Dots, Quantum optics}, issn = {1530-6984}, doi = {10.1021/acs.nanolett.9b02758}, author = {Schnauber, Peter and Singh, Anshuman and Schall, Johannes and Park, Suk In and Song, Jin Dong and Rodt, Sven and Srinivasan, Kartik and Reitzenstein, Stephan and Davanco, Marcelo} } @article { ISI:000457704900001, title = {Interacting Qubit-Photon Bound States with Superconducting Circuits}, journal = {PHYSICAL REVIEW X}, volume = {9}, number = {1}, year = {2019}, month = {FEB 1}, pages = {011021}, issn = {2160-3308}, doi = {10.1103/PhysRevX.9.011021}, author = {Sundaresan, Neereja M. and Lundgren, Rex and Zhu, Guanyu and Gorshkov, V, Alexey and Houck, Andrew A.} } @article {ISI:000467378000002, title = {Interplay between magnetic and vestigial nematic orders in the layered J(1)-J(2) classical Heisenberg model}, journal = {Phys. Rev. B}, volume = {99}, number = {17}, year = {2019}, month = {MAY 6}, pages = {174404}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We study the layered J(1)-J(2) classical Heisenberg model on the square lattice using a self-consistent bond theory. We derive the phase diagram for fixed J(1) as a function of temperature T, J(2), and interplane coupling J(z). Broad regions of (anti)ferromagnetic and stripe order are found, and are separated by a first-order transition near J(2) approximate to 0.5 (in units of vertical bar J(1)vertical bar). Within the stripe phase the magnetic and vestigial nematic transitions occur simultaneously in first-order fashion for strong J(z). For weaker J(z), there is in addition, for J(2){*} < J(2) < J(2){*}{*}, an intermediate regime of split transitions implying a finite temperature region with nematic order but no long-range stripe magnetic order. In this split regime, the order of the transitions depends sensitively on the deviation from J(2){*} and J(2){*}{*}, with split second-order transitions predominating for J(2){*} << J(2) << J(2){*}{*}. We find that the value of J(2){*} depends weakly on the interplane coupling and is just slightly larger than 0.5 for vertical bar J(z)vertical bar less than or similar to 0.01. In contrast, the value of J(2){*}{*} increases quickly from J(2){*} at vertical bar J(z)vertical bar less than or similar to 0.01 as the interplane coupling is further reduced. In addition, the magnetic correlation length is shown to directly depend on the nematic order parameter and thus exhibits a sharp increase (or jump) upon entering the nematic phase. Our results are broadly consistent with the predictions based on itinerant electron models of the iron-based superconductors in the normal state and, thus, help substantiate a classical spin framework for providing a phenomenological description of their magnetic properties.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.99.174404}, author = {Syljuasen, Olav F. and Paaske, Jens and Schecter, Michael} } @article {ISI:000474892400001, title = {Locality and Digital Quantum Simulation of Power-Law Interactions}, journal = {Phys. Rev. X}, volume = {9}, number = {3}, year = {2019}, month = {JUL 10}, pages = {031006}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {The propagation of information in nonrelativistic quantum systems obeys a speed limit known as a Lieb-Robinson bound. We derive a new Lieb-Robinson bound for systems with interactions that decay with distance r as a power law, 1/r(alpha). The bound implies an effective light cone tighter than all previous bounds. Our approach is based on a technique for approximating the time evolution of a system, which was first introduced as part of a quantum simulation algorithm by Haah et al., FOCS{\textquoteright} 18. To bound the error of the approximation, we use a known Lieb-Robinson bound that is weaker than the bound we establish. This result brings the analysis full circle, suggesting a deep connection between Lieb-Robinson bounds and digital quantum simulation. In addition to the new Lieb-Robinson bound, our analysis also gives an error bound for the Haah et al. quantum simulation algorithm when used to simulate power-law decaying interactions. In particular, we show that the gate count of the algorithm scales with the system size better than existing algorithms when alpha > 3D (where D is the number of dimensions).}, issn = {2160-3308}, doi = {10.1103/PhysRevX.9.031006}, author = {Tran, Minh C. and Guo, Andrew Y. and Su, Yuan and Garrison, James R. and Eldredge, Zachary and Foss-Feig, Michael and Childs, Andrew M. and Gorshkov, Alexey V.} } @article { ISI:000501342800003, title = {Measurement of the 7p P-2(3/2) state branching fractions in Ra+}, journal = {Phys. Rev. A}, volume = {100}, number = {6}, year = {2019}, month = {DEC 6}, pages = {062504}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We report a measurement of the radium ion{\textquoteright}s 7p(2)P(3/2) state branching fractions and improved theoretical calculations. With a single laser-cooled Ra-226(+) ion we measure the P-3/2 branching fractions to the 7s(2)S(1/2) ground state 0.876 78(20), the 6d D-2(5/2) state 0.107 59(10), and the 6d D-2(3/2) state 0.015 63(21).}, issn = {2469-9926}, doi = {10.1103/PhysRevA.100.062504}, author = {Fan, M. and Holliman, C. A. and Porsev, S. G. and Safronova, M. S. and Jayich, A. M.} } @article {ISI:000469016300011, title = {Measurement-induced dynamics and stabilization of spinor-condensate domain walls}, journal = {Phys. Rev. A}, volume = {99}, number = {5}, year = {2019}, month = {MAY 22}, pages = {053612}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Weakly measuring many-body systems and allowing for feedback in real time can simultaneously create and measure new phenomena in quantum systems. We theoretically study the dynamics of a continuously measured two-component Bose-Einstein condensate (BEC) potentially containing a domain wall and focus on the tradeoff between usable information obtained from measurement and quantum backaction. Each weakly measured system yields a measurement record from which we extract real-time dynamics of the domain wall. We show that quantum backaction due to measurement causes two primary effects: domain-wall diffusion and overall heating. The system dynamics and signal-to-noise ratio depend on the choice of measurement observable. We propose a feedback protocol to dynamically create a stable domain wall in the regime where domain walls are unstable, giving a prototype example of Hamiltonian engineering using measurement and feedback.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.99.053612}, author = {Hurst, Hilary M. and Spielman, I. B.} } @article {ISI:000483578600012, title = {Measurements of the branching ratios for 6P(1/2) decays in Ba-138(+)}, journal = {Phys. Rev. A}, volume = {100}, number = {3}, year = {2019}, month = {SEP 3}, pages = {032503}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Measurement of the branching ratios for 6P(1/2) decays to 6S(1/2) and 5D(3/2) in Ba-138(+) are reported with the decay probability from 6P(1/2) to 5D(3/2) measured to be p = 0.268177 +/- (37)(stat)-(20)(sys). This result differs from a recent report by 12 sigma. A detailed account of systematics is given, and the likely source of the discrepancy is identified. The new value of the branching reported here is combined with previous experimental results to give a new estimate of tau = 7.855(10) ns for the 6P(1/2) lifetime. In addition, ratios of matrix elements calculated from theory are combined with experimental results to provide improved theoretical estimates of the 6P(3/2) lifetime and the associated matrix elements.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.100.032503}, author = {Arnold, K. J. and Chanu, S. R. and Kaewuam, R. and Tan, T. R. and Yeo, L. and Zhang, Zhiqiang and Safronova, M. S. and Barrett, M. D.} } @article {ISI:000466709400015, title = {Microcontroller based scanning transfer cavity lock for long-term laser frequency stabilization}, journal = {Rev. Sci. Instrum.}, volume = {90}, number = {4}, year = {2019}, month = {APR}, pages = {043115}, publisher = {AMER INST PHYSICS}, type = {Article}, abstract = {We present a compact all-digital implementation of a scanning transfer cavity lock (STCL) for long-term laser frequency stabilization. An interrupt-driven state machine is employed to realize the STCL with the capability to correct for frequency drifts in the slave laser frequency due to measured changes in the lab environmental conditions. We demonstrate an accuracy of 0.9 MHz for master laser and slave laser wavelengths of 556 nm and 798 nm as an example. The slave laser is also demonstrated to dynamically scan over a wide frequency range while retaining its lock, allowing us to accurately interrogate atomic transitions. Published under license by AIP Publishing.}, issn = {0034-6748}, doi = {10.1063/1.5067266}, author = {Subhankar, S. and Restelli, A. and Wang, Y. and Rolston, S. L. and Porto, J. V.} } @article { ISI:000504926700014, title = {Milliwatt-threshold visible-telecom optical parametric oscillation using silicon nanophotonics}, journal = {Optica}, volume = {6}, number = {12}, year = {2019}, month = {DEC 20}, pages = {1535-1541}, publisher = {OPTICAL SOC AMER}, type = {Article}, abstract = {The on-chip creation of coherent light at visible wavelengths is crucial to field-level deployment of spectroscopy and metrology systems. Although on-chip lasers have been implemented in specific cases, a general solution that is not restricted by limitations of specific gain media has not been reported, to the best of our knowledge. Here, we propose creating visible light from an infrared pump by widely separated optical parametric oscillation (OPO) using silicon nanophotonics. The OPO creates signal and idler light in the 700 nm and 1300 nm bands, respectively, with a 900 nm pump. It operates at a threshold power of (0.9 +/- 0.1) mW, over 50 x smaller than other widely separated microcavity OPO works, which have been reported only in the infrared. This low threshold enables direct pumping without need of an intermediate optical amplifier. We further show how the device design can be modified to generate 780 nm and 1500 nm light with a similar power efficiency. Our nanophotonic OPO shows distinct advantages in power efficiency, operation stability, and device scalability, and is a major advance towards flexible on-chip generation of coherent visible light.}, issn = {2334-2536}, doi = {10.1364/OPTICA.6.001535}, author = {Lu, Xiyuan and Moille, Gregory and Singh, Anshuman and Li, Qing and Westly, Daron A. and Rao, Ashutosh and Yu, Su-Peng and Briles, Travis C. and Papp, Scott B. and Srinivasan, Kartik} } @article {14436, title = {Nanoscale Atomic Density Microscopy}, journal = {Phys. Rev. X}, volume = {9}, year = {2019}, month = {Apr}, pages = {021002}, doi = {10.1103/PhysRevX.9.021002}, url = {https://link.aps.org/doi/10.1103/PhysRevX.9.021002}, author = {Subhankar, S. and Wang, Y. and Tsui, T-C. and Rolston, S. L. and Porto, J. V.} } @article {ISI:000485768100009, title = {Narrow-line Cooling and Determination of the Magic Wavelength of Cd}, journal = {Phys. Rev. Lett.}, volume = {123}, number = {11}, year = {2019}, month = {SEP 13}, pages = {113201}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We experimentally and theoretically determine the magic wavelength of the (5s(2))S-1(0) - (5s5p)P-3(0) clock transition of Cd-111 to be 419.88(14) and 420.1(7) nm. To perform Lamb-Dicke spectroscopy of the clock transition, we use narrow-line laser cooling on the S-1(0) - P-3(1) transition to cool the atoms to 6 mu K and load them into an optical lattice. Cadmium is an attractive candidate for optical lattice clocks because it has a small sensitivity to blackbody radiation and its efficient narrow-line cooling mitigates higher order light shifts. We calculate the blackbody shift, including the dynamic correction, to be fractionally 2.83(8) x 10(-16) at 300 K, an order of magnitude smaller than that of Sr and Yb. We also report calculations of the Cd P-1(1) lifetime and the ground state C-6 coefficient.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.123.113201}, author = {Yamaguchi, A. and Safronova, M. S. and Gibble, K. and Katori, H.} } @article {ISI:000456484300001, title = {Neutral-Atom Wavelength-Compatible 780 nm Single Photons from a Trapped Ion via Quantum Frequency Conversion}, journal = {Phys. Rev. Appl.}, volume = {11}, number = {1}, year = {2019}, month = {JAN 23}, pages = {014044}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {The interfacing of quantum platforms via photonic links is a precursor for establishing scalable quantum networks. The connection of different types of quantum memories for hybrid networking requires the overcoming of the disparate photon wavelengths emitted by each quantum memory. Given achievements in quantum information processing with trapped-ion and neutral-atom architectures, a hybrid system with modular interconnectivity is advantageous. Here, we use a trapped Ba-138(+) ion and a periodically poled lithium-niobate (PPLN) waveguide, with a fiber-coupled output, to demonstrate 19\% end-to-end efficient quantum frequency conversion (QFC) of single photons from 493 to 780 nm and use fluorescence of the ion to produce light at the Rb-87 D-2 transition wavelength. To demonstrate the quantum nature of both the unconverted 493 nm photons and the converted photons near 780 nm, we observe strong quantum statics in their respective second-order intensity correlations. This work extends the range of intralaboratory networking between ions and networking between disparate quantum memories.}, issn = {2331-7019}, doi = {10.1103/PhysRevApplied.11.014044}, author = {Siverns, James D. and Hannegan, John and Quraishi, Qudsia} } @article {ISI:000467042000002, title = {Observation of Many-Body Localization in a One-Dimensional System with a Single-Particle Mobility Edge}, journal = {Phys. Rev. Lett.}, volume = {122}, number = {17}, year = {2019}, month = {MAY 3}, pages = {170403}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We experimentally study many-body localization (MBL) with ultracold atoms in a weak onedimensional quasiperiodic potential, which in the noninteracting limit exhibits an intermediate phase that is characterized by a mobility edge. We measure the time evolution of an initial charge density wave after a quench and analyze the corresponding relaxation exponents. We find clear signatures of MBL when the corresponding noninteracting model is deep in the localized phase. We also critically compare and contrast our results with those from a tight-binding Aubry-Andre model, which does not exhibit a singleparticle intermediate phase, in order to identify signatures of a potential many-body intermediate phase.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.122.170403}, author = {Kohlert, Thomas and Scherg, Sebastian and Li, Xiao and Lueschen, Henrik P. and S. Das Sarma and Bloch, Immanuel and Aidelsburger, Monika} } @article {ISI:000461126600036, title = {Optical clock comparison for Lorentz symmetry testing}, journal = {Nature}, volume = {567}, number = {7747}, year = {2019}, month = {MAR 14}, pages = {204+}, publisher = {NATURE PUBLISHING GROUP}, type = {Article}, abstract = {Questioning basic assumptions about the structure of space and time has greatly enhanced our understanding of nature. State-of-the-art atomic clocks(1-3) make it possible to precisely test fundamental symmetry properties of spacetime and search for physics beyond the standard model at low energies of just a few electronvolts(4). Modern tests of Einstein{\textquoteright}s theory of relativity try to measure so-far-undetected violations of Lorentz symmetry(5); accurately comparing the frequencies of optical clocks is a promising route to further improving such tests(6). Here we experimentally demonstrate agreement between two single-ion optical clocks at the 10(-18) level, directly validating their uncertainty budgets, over a six-month comparison period. The ytterbium ions of the two clocks are confined in separate ion traps with quantization axes aligned along non-parallel directions. Hypothetical Lorentz symmetry violations(5-7) would lead to periodic modulations of the frequency offset as the Earth rotates and orbits the Sun. From the absence of such modulations at the 10(-19) level we deduce stringent limits of the order of 10(-21) on Lorentz symmetry violation parameters for electrons, improving previous limits(8-10) by two orders of magnitude. Such levels of precision will be essential for low-energy tests of future quantum gravity theories describing dynamics at the Planck scale(4), which are expected to predict the magnitude of residual symmetry violations.}, issn = {0028-0836}, doi = {10.1038/s41586-019-0972-2}, author = {Sanner, Christian and Huntemann, Nils and Lange, Richard and Tamm, Christian and Peik, Ekkehard and Safronova, Marianna S. and Porsev, Sergey G.} } @article {14481, title = {Perfect Andreev reflection due to the Klein paradox in a topological superconducting state}, journal = {Nature}, volume = {570}, year = {2019}, pages = {344{\textendash}348}, abstract = {In 1928, Dirac proposed a wave equation to describe relativistic electrons1. Shortly afterwards, Klein solved a simple potential step problem for the Dirac equation and encountered an apparent paradox: the potential barrier becomes transparent when its height is larger than the electron energy. For massless particles, backscattering is completely forbidden in Klein tunnelling, leading to perfect transmission through any potential barrier2,3. The recent advent of condensed-matter systems with Dirac-like excitations, such as graphene and topological insulators, has opened up the possibility of observing Klein tunnelling experimentally4{\textendash}6. In the surface states of topological insulators, fermions are bound by spin{\textendash}momentum locking and are thus immune from backscattering, which is prohibited by time-reversal symmetry. Here we report the observation of perfect Andreev reflection in point-contact spectroscopy{\textendash}-a clear signature of Klein tunnelling and a manifestation of the underlying {\textquoteleft}relativistic{\textquoteright}physics of a proximity-induced superconducting state in a topological Kondo insulator. Our findings shed light on a previously overlooked aspect of topological superconductivity and can serve as the basis for a unique family of spintronic and superconducting devices, the interface transport phenomena of which are completely governed by their helical topological states.

}, isbn = {1476-4687}, doi = {10.1038/s41586-019-1305-1}, url = {https://doi.org/10.1038/s41586-019-1305-1}, author = {Lee, Seunghun and Stanev, Valentin and Zhang, Xiaohang and Stasak, Drew and Flowers, Jack and Higgins, Joshua S. and Dai, Sheng and Blum, Thomas and Pan, Xiaoqing and Yakovenko, Victor M. and Paglione, Johnpierre and Greene, Richard L. and Galitski, Victor and Takeuchi, Ichiro} } @article {21371, title = {Phonon-induced giant linear-in-T resistivity in magic angle twisted bilayer graphene: Ordinary strangeness and exotic superconductivity}, journal = {Phys. Rev. B}, volume = {99}, year = {2019}, month = {Apr}, pages = {165112}, abstract = {We study the effect of electron-acoustic phonon interactions in twisted bilayer graphene on resistivity in the high-temperature transport and superconductivity in the low-temperature phase diagram. We theoretically show that twisted bilayer graphene should have an enhanced and strongly twist-angle dependent linear-in-temperature resistivity in the metallic regime with the resistivity magnitude increasing as the twist angle approaches the magic angle. The slope of the resistivity versus temperature could approach one hundred ohm per kelvin with a strong angle dependence, but with a rather weak dependence on the carrier density. This higher-temperature density-independent linear-in-T\ resistivity crosses over to a\ T4\ dependence at a low density-dependent characteristic temperature, becoming unimportant at low temperatures. This angle-tuned resistivity enhancement arises from the huge increase in the effective electron-acoustic phonon coupling in the system due to the suppression of graphene Fermi velocity induced by the flat-band condition in the moir{\'e} superlattice system. Our calculated temperature dependence is reminiscent of the so-called {\textquotedblleft}strange metal{\textquotedblright} transport behavior except that it is arising from the ordinary electron-phonon coupling in a rather unusual parameter space due to the generic moir{\'e} flat-band structure of twisted bilayer graphene. We also show that the same enhanced electron-acoustic phonon coupling also mediates effective attractive interactions in\ s,p,d, and\ f\ pairing channels with a theoretical superconducting transition temperature on the order of\ \~{}5\ K near magic angle. The fact that ordinary acoustic phonons can produce exotic non-s-wave superconducting pairing arises from the unusual symmetries of the system.

}, doi = {10.1103/PhysRevB.99.165112}, url = {https://link.aps.org/doi/10.1103/PhysRevB.99.165112}, author = {Wu, Fengcheng and Hwang, Euyheon and Das Sarma, Sankar} } @article {ISI:000479005400008, title = {Photon Pair Condensation by Engineered Dissipation}, journal = {Phys. Rev. Lett.}, volume = {123}, number = {6}, year = {2019}, month = {AUG 6}, pages = {063602}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Dissipation can usually induce detrimental decoherence in a quantum system. However, engineered dissipation can be used to prepare and stabilize coherent quantum many-body states. Here, we show that, by engineering dissipators containing photon pair operators, one can stabilize an exotic dark state, which is a condensate of photon pairs with a phase-nematic order. In this system, the usual superfluid order parameter, i.e., single-photon correlation, is absent, while the photon pair correlation exhibits long-range order. Although the dark state is not unique due to multiple parity sectors, we devise an additional type of dissipators to stabilize the dark state in a particular parity sector via a diffusive annihilation process which obeys Glauber dynamics in an Ising model. Furthermore, we propose an implementation of these photon pair dissipators in circuit-QED architecture.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.123.063602}, author = {Cian, Ze-Pei and Zhu, Guanyu and Chu, Su-Kuan and Seif, Alireza and DeGottardi, Wade and Jiang, Liang and Hafezi, Mohammad} } @article { ISI:000492332900006, title = {Polarizability assessments of ion-based optical clocks}, journal = {Phys. Rev. A}, volume = {100}, number = {4}, year = {2019}, month = {OCT 24}, pages = {043418}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {It is shown that the dynamic differential scalar polarizability of the S-1/2 - D-5/2 transition in Ba-138(+) can be determined to an inaccuracy below 0.5\% across a wide wavelength range (lambda > 700 nm). This can be achieved using measurements for which accurate determination of laser intensity is not required, and most of the required measurements are already in the literature. Measurement of a laser-induced ac-Stark shift of the clock transition would then provide an in situ measurement of the laser{\textquoteright}s intensity to the same 0.5\% level of inaccuracy, which is not easily achieved by other means. This would allow accurate polarizability measurements for clock transitions in other ions, through comparison with Ba-138(+). The approach would be equally applicable to Sr+ and Ca+, with the latter being immediately applicable to Al+/Ca+ quantum logic clocks.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.100.043418}, author = {Barrett, M. D. and Arnold, K. J. and Safronova, M. S.} } @article {ISI:000454776000002, title = {Possible Hundredfold Enhancement in the Direct Magnetic Coupling of a Single-Atom Electron Spin to a Circuit Resonator}, journal = {Phys. Rev. Appl.}, volume = {11}, number = {1}, year = {2019}, month = {JAN 2}, pages = {014001}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We report on the challenges and limitations of direct coupling of the magnetic field from a circuit resonator to an electron spin bound to a donor potential. We propose a device consisting of a trilayer lumped-element superconducting resonator and a single donor implanted in enriched Si-28. The resonator impedance is significantly smaller than the practically achievable limit obtained with prevalent coplanar resonators. Furthermore, the resonator includes a nanoscale spiral inductor to spatially focus the magnetic field from the photons at the location of the implanted donor. The design promises an increase of approximately 2 orders of magnitude in the local magnetic field, and thus the spin-to-photon coupling rate g, compared with the estimated rate of coupling to the magnetic field of coplanar transmission line resonators. We show that by use of niobium (aluminum) as the resonator{\textquoteright}s superconductor and a single phosphorous (bismuth) atom as the donor, a coupling rate of g/2 pi = 0.24 MHz (0.39 MHz) can be achieved in the single-photon regime. For this hybrid cavity-quantum-electrodynamic system, such enhancement in g is sufficient to enter the strong-coupling regime.}, issn = {2331-7019}, doi = {10.1103/PhysRevApplied.11.014001}, author = {Sarabi, Bahman and Huang, Peihao and Zimmerman, Neil M.} } @article {ISI:000474369000008, title = {Presence versus absence of end-to-end nonlocal conductance correlations in Majorana nanowires: Majorana bound states versus Andreev bound states}, journal = {Phys. Rev. B}, volume = {100}, number = {4}, year = {2019}, month = {JUL 3}, pages = {045302}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {By calculating the differential tunneling conductance spectra from the two ends of a Majorana nanowire with a quantum dot embedded at one end, we establish that a careful examination of the nonlocal correlations of the zero-bias conductance peaks, as measured separately from the two ends of the wire, can distinguish between topological Majorana bound states and trivial Andreev bound states. In particular, there will be identical correlated zero-bias peaks from both ends for Majorana bound states, and thus the presence of correlated zero-bias conductance from the two wire ends could imply the presence of topological Majorana zero modes in the system. On the contrary, there will not be identical correlated zero-bias peaks from both ends for Andreev bound states, so the absence of correlated zero-bias conductance from the two wire ends implies the absence of topological Majorana zero modes in the system. We present detailed results for the calculated conductance, energy spectra, and wave functions for different chemical potentials at the same magnetic field values to motivate end-to-end conductance correlation measurements in Majorana nanowires.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.100.045302}, author = {Lai, Yi-Hua and Sau, Jay D. and S. Das Sarma} } @article {ISI:000462932400012, title = {Proposal for Measuring the Parity Anomaly in a Topological Superconductor Ring}, journal = {Phys. Rev. Lett.}, volume = {122}, number = {11}, year = {2019}, month = {MAR 22}, pages = {117001}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {A topological superconductor ring is uniquely characterized by a switch in the ground state fermion number parity upon insertion of one superconducting flux quantum-a direct consequence of the topological {\textquoteleft}{\textquoteleft}parity anomaly.{{\textquoteright}{\textquoteright}} Despite the many other tantalizing signatures and applications of topological superconductors, this fundamental, defining property remains to be observed experimentally. Here we propose definitive detection of the fermion parity switch from the charging energy, temperature, and tunnel barrier dependence of the flux periodicity of two-terminal conductance of a floating superconductor ring. We extend the Ambegaokar-Eckern-Schon formalism for superconductors with a Coulomb charging energy to establish new explicit relationships between thermodynamic and transport properties of such a ring and the topological invariant of the superconductor. Crucially, we show that the topological contribution to the conductance oscillations can be isolated from Aharonov-Bohm oscillations of nontopological origin by their different dependence on the charging energy or barrier transparency.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.122.117001}, author = {Liu, Chun-Xiao and Cole, William S. and Sau, Jay D.} } @article {ISI:000471060400001, title = {pyLLE: A Fast and User Friendly Lugiato-Lefever Equation Solver}, journal = {J. Res. Natl. Inst. Stand. Technol.}, volume = {124}, year = {2019}, month = {MAY 24}, pages = {012}, publisher = {NATL INST STANDARDS \& TECHNOLOGY-NIST}, type = {Article}, keywords = {Julia, micro-combs, non-linear optics, python}, issn = {2165-7254}, doi = {10.6028/jres.124.012}, author = {Moille, Gregory and Li, Qing and Lu, Xiyuan and Srinivasan, Kartik} } @article {ISI:000468373300008, title = {Quantum frequency conversion of a quantum dot single-photon source on a nanophotonic chip}, journal = {Optica}, volume = {6}, number = {5}, year = {2019}, month = {MAY 20}, pages = {563-569}, publisher = {OPTICAL SOC AMER}, type = {Article}, abstract = {Single self-assembled InAs/GaAs quantum dots are promising bright sources of indistinguishable photons for quantum information science. However, their distribution in emission wavelength, due to inhomogeneous broadening inherent to their growth, has limited the ability to create multiple identical sources. Quantum frequency conversion can overcome this issue, particularly if implemented using scalable chip-integrated technologies. Here, we report the first demonstration to our knowledge of quantum frequency conversion of a quantum dot single-photon source on a silicon nanophotonic chip. Single photons from a quantum dot in a micropillar cavity are shifted in wavelength with an on-chip conversion efficiency approximate to 12\%, limited by the linewidth of the quantum dot photons. The intensity auto-correlation function g((2)) (tau) for the frequency-converted light is antibunched with g((2)) (0) = 0.290 +/- 0.030, compared to the before-conversion value g((2)) (0) = 0.080 +/- 0.003. We demonstrate the suitability of our frequency-conversion interface as a resource for quantum dot sources by characterizing its effectiveness across a wide span of input wavelengths (840-980 nm) and its ability to achieve tunable wavelength shifts difficult to obtain by other approaches. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement}, issn = {2334-2536}, doi = {10.1364/OPTICA.6.000563}, author = {Singh, Anshuman and Li, Qing and Liu, Shunfa and Yu, Ying and Lu, Xiyuan and Schneider, Christian and Hoefling, Sven and Lawall, John and Verma, Varun and Mirin, Richard and Nam, Sae Woo and Liu, Jin and Srinivasan, Kartik} } @article { ISI:000496930000002, title = {Quantum Interference between Photons from an Atomic Ensemble and a Remote Atomic Ion}, journal = {Phys. Rev. Lett.}, volume = {123}, number = {21}, year = {2019}, month = {NOV 18}, pages = {213601}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Many remote-entanglement protocols rely on the generation and interference of photons produced by nodes within a quantum network. Quantum networks based on heterogeneous nodes provide a versatile platform by utilizing the complementary strengths of the differing systems. Implementation of such networks is challenging, due to the disparate spectral and temporal characteristics of the photons generated by the different quantum systems. Here, we report on the observation of quantum interference between photons generated from a single ion and an atomic ensemble. The photons are produced on demand by each source located in separate buildings, in a manner suitable for quantum networking. Given these results, we analyze the feasibility of hybrid ion-ensemble remote entanglement generation.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.123.213601}, author = {Craddock, A. N. and Hannegan, J. and Ornelas-Huerta, D. P. and Siverns, J. D. and Hachtel, A. J. and Goldschmidt, A. and Porto, J. V. and Quraishi, Q. and Rolston, S. L.} } @article { ISI:000498849400002, title = {Quantum many-body scars from magnon condensation}, journal = {Phys. Rev. B}, volume = {100}, number = {18}, year = {2019}, month = {NOV 27}, pages = {184312}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We study the eigenstate properties of a nonintegrable spin chain that was recently realized experimentally in a Rydberg-atom quantum simulator. In the experiment, long-lived coherent many-body oscillations were observed only when the system was initialized in a particular product state. This pronounced coherence has been attributed to the presence of special {\textquoteleft}{\textquoteleft}scarred{{\textquoteright}{\textquoteright}} eigenstates with nearly equally spaced energies and putative nonergodic properties despite their finite energy density. In this paper we uncover a surprising connection between these scarred eigenstates and low-lying quasiparticle excitations of the spin chain. In particular, we show that these eigenstates can be accurately captured by a set of variational states containing a macroscopic number of magnons with momentum pi. This leads to an interpretation of the scarred eigenstates as finite-energy-density condensates of weakly interacting pi magnons. One natural consequence of this interpretation is that the scarred eigenstates possess long-range connected correlations in both space and time. We verify numerically the presence of this spatiotemporal long-range order and explain how it is consistent with established no-go theorems precluding its existence in ground states and at thermal equilibrium.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.100.184312}, author = {Iadecola, Thomas and Schecter, Michael and Xu, Shenglong} } @article {ISI:000476860700002, title = {Quantum repeaters based on two species trapped ions}, journal = {New J. Phys.}, volume = {21}, year = {2019}, month = {JUL 1}, pages = {073002}, publisher = {IOP PUBLISHING LTD}, type = {Article}, abstract = {We examine the viability of quantum repeaters based on two-species trapped ion modules for long-distance quantum key distribution. Repeater nodes comprised of ion-trap modules of co-trapped ions of distinct species are considered. The species used for communication qubits has excellent optical properties while the other longer lived species serves as a memory qubit in the modules. Each module interacts with the network only via single photons emitted by the communication ions. Coherent Coulomb interaction between ions is utilized to transfer quantum information between the communication and memory ions and to achieve entanglement swapping between two memory ions. We describe simple modular quantum repeater architectures realizable with the ion-trap modules and numerically study the dependence of the quantum key distribution rate on various experimental parameters, including coupling efficiency, gate infidelity, operation time and length of the elementary links. Our analysis suggests crucial improvements necessary in a physical implementation for co-trapped two-species ions to be a competitive platform in long-distance quantum communication.}, keywords = {quantum key distribution, quantum repeaters, two species trapped ions}, issn = {1367-2630}, doi = {10.1088/1367-2630/ab2a45}, author = {Santra, Siddhartha and Muralidharan, Sreraman and Lichtman, Martin and Jiang, Liang and Monroe, Christopher and Malinovsky, Vladimir S.} } @conference {ISI:000482226301355, title = {Quantum-correlated Light Source from Dual-seeded Four-wave Mixing with a Diode Laser System}, booktitle = {2019 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO)}, series = {Conference on Lasers and Electro-Optics}, year = {2019}, note = {Conference on Lasers and Electro-Optics (CLEO), San Jose, CA, MAY 05-10, 2019}, publisher = {IEEE; AdValue Photon; Amer Elements; Class5 Photon; Coherent; GoFoton; Light Convers; LightTrans; MKS; OZ Opt Online; Santec; ThorLabs; UQDevices; YSL Photon}, organization = {IEEE; AdValue Photon; Amer Elements; Class5 Photon; Coherent; GoFoton; Light Convers; LightTrans; MKS; OZ Opt Online; Santec; ThorLabs; UQDevices; YSL Photon}, type = {Proceedings Paper}, abstract = {We have obtained broadband intensity-difference squeezing from sub 10 Hz to 20 MHz via four-wave mixing (4WM) in a rubidium vapor. This was accomplished by dual-seeding the 4WM process and using semiconductor diode lasers. (C) 2019 The Author(s)}, isbn = {978-1-943580-57-6}, issn = {2160-9020}, author = {Wu, Meng-Chang and Brewer, Nicholas R. and Speirs, Rory W. and Schmittberger, Bonnie L. and Jones, Kevin M. and Lett, Paul D.} } @article { ISI:000503978100047, title = {Repeated measurements with minimally destructive partial-transfer absorption imaging}, journal = {Opt. Express}, volume = {27}, number = {25}, year = {2019}, month = {DEC 9}, pages = {36611-36624}, publisher = {OPTICAL SOC AMER}, type = {Article}, abstract = {We demonstrate partial-transfer absorption imaging as a technique for repeatedly imaging an ultracold atomic ensemble with minimal perturbation. We prepare an atomic cloud in a state that is dark to the imaging light. We then use a microwave pulse to coherently transfer a small fraction of the ensemble to a bright state, which we image using in situ absorption imaging. The amplitude or duration of the microwave pulse controls the fractional transfer from the dark to the bright state. For small transfer fractions, we can image the atomic cloud up to 50 times before it is depleted. As a sample application, we repeatedly image an atomic cloud oscillating in a dipole trap to measure the trap frequency. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement}, issn = {1094-4087}, doi = {10.1364/OE.27.036611}, author = {Seroka, Erin Marshall and Curiel, Ana Valdes and Trypogeorgos, Dimitrios and Lundblad, Nathan and Spielman, Ian B.} } @article { ISI:000500743400001, title = {Rydberg-Mediated Entanglement in a Two-Dimensional Neutral Atom Qubit Array}, journal = {Phys. Rev. Lett.}, volume = {123}, number = {23}, year = {2019}, month = {DEC 4}, pages = {230501}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We demonstrate high fidelity two-qubit Rydberg blockade and entanglement on a pair of sites in a large two-dimensional qubit array. The qubit array is defined by a grid of blue detuned lines of light with 121 sites for trapping atomic qubits. Improved experimental methods have increased the observed Bell state fidelity to F-Bell = 0.86(2). Accounting for errors in state preparation and measurement we infer a fidelity of F-(SPAM)(Bell) = 0.88. Accounting for errors in single qubit operations we infer that a Bell state created with the Rydberg mediated C-Z gate has a fidelity of F-Bell(CZ) = 0.89. Comparison with a detailed error model based on quantum process matrices indicates that finite atom temperature and laser noise are the dominant error sources contributing to the observed gate infidelity.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.123.230501}, author = {Graham, T. M. and Kwon, M. and Grinkemeyer, B. and Marra, Z. and Jiang, X. and Lichtman, M. T. and Sun, Y. and Ebert, M. and Saffman, M.} } @article {ISI:000482547000001, title = {Sauter-Schwinger effect with a quantum gas}, journal = {New J. Phys.}, volume = {21}, year = {2019}, month = {AUG 21}, pages = {083035}, publisher = {IOP PUBLISHING LTD}, type = {Article}, abstract = {The creation of particle-antiparticle pairs from vacuum by a large electric field is at the core of quantum electrodynamics. Despite the wide acceptance that this phenomenon occurs naturally when electric field strengths exceed E-c approximate to 10(18) Vm(-1), it has yet to be experimentally observed due to the limitations imposed by producing electric fields at this scale. The high degree of experimental control present in ultracold atomic systems allow experimentalists to create laboratory analogs to high-field phenomena. Here we emulated massive relativistic particles subject to large electric field strengths, thereby quantum-simulated particle-antiparticle pair creation, and experimentally explored particle creation from {\textquoteleft}the Dirac vacuum{\textquoteright}. Data collected from our analog system spans the full parameter regime from low applied field (negligible pair creation) below the Sauter-Schwinger limit, to high field (maximum rate of pair creation) far in excess of the Sauter-Schwinger limit. In our experiment, we perform direct measurements on an analog atomic system and show that this high-field phenomenon is well-characterized by Landau-Zener tunneling, well known in the atomic physics context, and we find full quantitative agreement with theory with no adjustable parameters.}, keywords = {particle creation, quantum gases, quantum simulation, Sauter-Schwinger effect}, issn = {1367-2630}, doi = {10.1088/1367-2630/ab3840}, author = {Pineiro, A. M. and Genkina, D. and Lu, Mingwu and Spielman, I. B.} } @article {ISI:000462935500003, title = {Scale-Invariant Continuous Entanglement Renormalization of a Chern Insulator}, journal = {Phys. Rev. Lett.}, volume = {122}, number = {12}, year = {2019}, month = {MAR 27}, pages = {120502}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {The multiscale entanglement renormalization ansatz (MERA) postulates the existence of quantum circuits that renormalize entanglement in real space at different length scales. Chem insulators, however, cannot have scale-invariant discrete MERA circuits with a finite bond dimension. In this Letter, we show that the continuous MERA (cMERA), a modified version of MERA adapted for field theories, possesses a fixed point wave function with a nonzero Chern number. Additionally, it is well known that reversed MERA circuits can be used to prepare quantum states efficiently in time that scales logarithmically with the size of the system. However, state preparation via MERA typically requires the advent of a full-fledged universal quantum computer. In this Letter, we demonstrate that our cMERA circuit can potentially be realized in existing analog quantum computers, i.e., an ultracold atomic Fermi gas in an optical lattice with light-induced spin-orbit coupling.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.122.120502}, author = {Chu, Su-Kuan and Zhu, Guanyu and Garrison, James R. and Eldredge, Zachary and Curiel, Ana Valdes and Bienias, Przemyslaw and Spielman, I. B. and Gorshkov, V, Alexey} } @article {ISI:000471993700016, title = {The Search for Variation of Fundamental Constants with Clocks}, journal = {Ann. Phys.-Berlin}, volume = {531}, number = {5, SI}, year = {2019}, month = {MAY}, pages = {1800364}, publisher = {WILEY-V C H VERLAG GMBH}, type = {Article}, abstract = {In many theories beyond the Standard Model the quantities that we call {\textquoteleft}{\textquoteleft}fundamental constants{{\textquoteright}{\textquoteright}} become space-time dependent, leading to corresponding variation of atomic and molecular spectra and clock frequencies. The extraordinary improvement of the atomic clock precision in the past fifteen years enabled testing the constancy of the fundamental constant at a very high level of precision. Herein, searches for the variation of fundamental constants with clocks are discussed, focusing on recent key results and future proposals, including highly charged ion, molecular, and nuclear clocks. The relevance of the recent searches for oscillatory and transient variation of fundamental constants to the major unexplained phenomena of our Universe, the nature of dark matter, is discussed.}, keywords = {atomic clocks, highly charged ions, nuclear clock, variation of fundamental constants}, issn = {0003-3804}, doi = {10.1002/andp.201800364}, author = {Safronova, Marianna S.} } @article { ISI:000490353500045, title = {A Spin-Photon Interface Using Charge-Tunable Quantum Dots Strongly Coupled to a Cavity}, journal = {Nano Lett.}, volume = {19}, number = {10}, year = {2019}, month = {OCT}, pages = {7072-7077}, publisher = {AMER CHEMICAL SOC}, type = {Article}, abstract = {Charged quantum dots containing an electron or hole spin are bright solid-state qubits suitable for quantum networks and distributed quantum computing. Incorporating such quantum dot spin into a photonic crystal cavity creates a strong spin-photon interface in which the spin can control a photon by modulating the cavity reflection coefficient. However, previous demonstrations of such spin-photon interfaces have relied on quantum dots that are charged randomly by nearby impurities, leading to instability in the charge state, which causes poor contrast in the cavity reflectivity. Here we demonstrate a strong spin-photon interface using a quantum dot that is charged deterministically with a diode structure. By incorporating this actively charged quantum dot in a photonic crystal cavity, we achieve strong coupling between the cavity mode and the negatively charged state of the dot. Furthermore, by initializing the spin through optical pumping, we show strong spin-dependent modulation of the cavity reflectivity, corresponding to a cooperativity of 12. This spin-dependent reflectivity is important for mediating entanglement between spins using photons, as well as generating strong photon-photon interactions for applications in quantum networking and distributed quantum computing.}, keywords = {cavity quantum electrodynamics, Quantum Dots, single electron spin, strong light-matter interaction}, issn = {1530-6984}, doi = {10.1021/acs.nanolett.9b02443}, author = {Luo, Zhouchen and Sun, Shuo and Karasahin, Aziz and Bracker, Allan S. and Carter, Samuel G. and Yakes, Michael K. and Gammon, Daniel and Waks, Edo} } @article { ISI:000492332900005, title = {Stroboscopic approach to trapped-ion quantum information processing with squeezed phonons}, journal = {Phys. Rev. A}, volume = {100}, number = {4}, year = {2019}, month = {OCT 24}, pages = {043417}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {In trapped-ion quantum information processing, interactions between spins (qubits) are mediated by collective modes of motion of an ion crystal. While there are many different experimental strategies to design such interactions, they all face both technical and fundamental limitations to the achievable coherent interaction strength. In general, obtaining strong interactions and fast gates is an ongoing challenge. Here, we extend previous work {[}W. Ge, B. C. Sawyer, J. W. Britton, K. Jacobs, J. J. Bollinger, and M. Foss-Feig, Phys. Rev. Lett. 122, 030501 (2019)] and present a general strategy for enhancing the interaction strengths in trapped-ion systems via parametric amplification of the ions{\textquoteright} motion. Specifically, we propose a stroboscopic protocol using alternating applications of parametric amplification and spin-motion coupling. In comparison with the previous work, we show that the current protocol can lead to larger enhancements in the coherent interaction that increase exponentially with the gate time.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.100.043417}, author = {Ge, Wenchao and Sawyer, Brian C. and Britton, Joseph W. and Jacobs, Kurt and Foss-Feig, Michael and Bollinger, John J.} } @conference {ISI:000466478500026, title = {Structured neutron waves}, booktitle = {OPTICAL, OPTO-ATOMIC, AND ENTANGLEMENT-ENHANCED PRECISION METROLOGY}, series = {Proceedings of SPIE}, volume = {10934}, year = {2019}, note = {Conference on Optical, Opto-Atomic, and Entanglement-Enhanced Precision Metrology, San Francisco, CA, FEB 02-07, 2019}, pages = {1093425}, publisher = {SPIE}, organization = {SPIE}, type = {Proceedings Paper}, abstract = {Emerging quantum materials are becoming the building blocks for quantum devices and they are enabling new advances from spintronics to topological insulators. Their functionality typically comes from their inner magnetic field structure. Neutrons are a particularly good probe to characterize such features. The control of neutron orbital angular momentum and the spin-orbit interaction enables new characterizing techniques and increased sensitivity towards specific material properties. Here we review the preparation and characterization methods of structured neutron waves.}, keywords = {Neutron Interferometry, Neutrons, orbital angular momentum, spin-orbit states, Structured Waves}, isbn = {978-1-5106-2511-2}, issn = {0277-786X}, doi = {10.1117/12.2515469}, author = {Sarenac, Dusan and Clark, Charles W. and Cory, David G. and Kapahi, Connor and Heacock, Benjamin and Huber, Michael G. and Nsofini, Joachim and Shahi, Chandra B. and Pushin, Dmitry A.}, editor = {Shahriar, SM and Scheuer, J} } @article { ISI:000492968000008, title = {Supercurrent interference in semiconductor nanowire Josephson junctions}, journal = {Phys. Rev. B}, volume = {100}, number = {15}, year = {2019}, month = {OCT 28}, pages = {155431}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Semiconductor-superconductor hybrid systems provide a promising platform for hosting unpaired Majorana fermions towards the realization of fault-tolerant topological quantum computing. In this study we employ the Keldysh nonequilibrium Green{\textquoteright}s function formalism to model quantum transport in normal-superconductor junctions. We analyze III-V semiconductor nanowire Josephson junctions (InAs/Nb) using a three-dimensional discrete lattice model described by the Bogoliubov-de Gennes Hamiltonian in the tight-binding approximation, and compute the Andreev bound state spectrum and current-phase relations. Recent experiments {[}Zuo et al., Phys. Rev. Lett. 119, 187704 (2017) and Gharavi et al., arXiv: 1405.7455] reveal critical current oscillations in these devices, and our simulations confirm these to be an interference effect of the transverse subbands in the nanowire. We add disorder to model coherent scattering and study its effect on the critical current oscillations, with an aim to gain a thorough understanding of the experiments. The oscillations in the disordered junction are highly sensitive to the particular realization of the random disorder potential, and to the gate voltage. A macroscopic current measurement thus gives us information about the microscopic profile of the junction. Finally, we study dephasing in the channel by including elastic phase-breaking interactions. The oscillations thus obtained are in good qualitative agreement with the experimental data, and this signifies the essential role of phase-breaking processes in III-V semiconductor nanowire Josephson junctions.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.100.155431}, author = {Sriram, Praveen and Kalantre, Sandesh S. and Gharavi, Kaveh and Baugh, Jonathan and Muralidharan, Bhaskaran} } @article {ISI:000479034100005, title = {Suppressing Inhomogeneous Broadening in a Lutetium Multi-ion Optical Clock}, journal = {Phys. Rev. Lett.}, volume = {123}, number = {6}, year = {2019}, month = {AUG 7}, pages = {063201}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We demonstrate precision measurement and control of inhomogeneous broadening in a multi-ion clock consisting of three Lu-176(+) ions. Microwave spectroscopy between hyperfine states in the D-3(1) level is used to characterize differential systematic shifts between ions, most notably those associated with the electric quadrupole moment. By appropriate alignment of the magnetic field, we demonstrate suppression of these effects to the similar to 10(-17) level relative to the S-1(0) <-> D-3(1) optical transition frequency. Correlation spectroscopy on the optical transition demonstrates the feasibility of a 10-s Ramsey interrogation in the three ion configuration with a corresponding projection noise limited stability of sigma(tau) = 8.2 x 10(-17)/root tau.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.123.063201}, author = {Tan, T. R. and Kaewuam, R. and Arnold, K. J. and Chanu, S. R. and Zhang, Zhiqiang and Safronova, M. S. and Barrett, M. D.} } @article {ISI:000461940700022, title = {Switchable detector array scheme to reduce the effect of single-photon detector{\textquoteright}s deadtime in a multi-bit/photon quantum link}, journal = {Opt. Commun.}, volume = {441}, year = {2019}, month = {JUN 15}, pages = {132-137}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, abstract = {{We explore the use of a switchable single-photon detector (SPD) array scheme to reduce the effect of a detector{\textquoteright}s deadtime for a multi-bit/photon quantum link. The case of data encoding using M possible orbital-angular-momentum (OAM) states is specifically studied in this paper. Our method uses N SPDs with a controllable M x N optical switch and we use a Monte Carlo-based method to simulate the quantum detection process. The simulation results show that with the use of the switchable SPD array, the detection system can allow a higher incident photon rate than what might otherwise be limited by detectors{\textquoteright} deadtime. For the case of M = 4}, keywords = {orbital angular momentum, quantum communication, Single photon detection}, issn = {0030-4018}, doi = {10.1016/j.optcom.2019.01.081}, author = {Liu, Cong and Ren, Yongxiong and Zhao, Jiapeng and Mirhosseini, Mohammad and Rafsanjani, Seyed Mohammad Hashemi and Xie, Guodong and Pang, Kai and Song, Haoqian and Zhao, Zhe and Wang, Zhe and Li, Long and Bienfang, Joshua C. and Migdall, Alan and Brun, Todd A. and Tur, Moshe and Boyd, Robert W. and Willner, Alan E.} } @article {ISI:000455826000001, title = {Tabletop experiments for quantum gravity: a user{\textquoteright}s manual}, journal = {Class. Quantum Gravity}, volume = {36}, number = {3}, year = {2019}, month = {FEB 7}, pages = {034001}, publisher = {IOP PUBLISHING LTD}, type = {Article}, abstract = {Recent advances in cooling, control, and measurement of mechanical systems in the quantum regime have opened the possibility of the first direct observation of quantum gravity, at scales achievable in experiments. This paper gives a broad overview of this idea, using some matter-wave and optomechanical systems to illustrate the predictions of a variety of models of low-energy quantum gravity. We first review the treatment of perturbatively quantized general relativity as an effective quantum field theory, and consider the particular challenges of observing quantum effects in this framework. We then move on to a variety of alternative models, such as those in which gravity is classical, emergent, or responsible for a breakdown of quantum mechanics.}, keywords = {experimental tests, Optomechanics, quantum gravity}, issn = {0264-9381}, doi = {10.1088/1361-6382/aaf9ca}, author = {Carney, Daniel and Stamp, Philip C. E. and Taylor, Jacob M.} } @article {ISI:000473009200001, title = {Theory of coherent phase modes in insulating Josephson junction chains}, journal = {Phys. Rev. B}, volume = {99}, number = {21}, year = {2019}, month = {JUN 21}, pages = {214509}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Recent microwave reflection measurements of Josephson junction chains have suggested the presence of nearly coherent collective charge oscillations deep in the insulating phase. Here we develop a qualitative understanding of such coherent charge modes by studying the local dynamical polarizability of the insulating phase of a finite length sine-Gordon model. By considering parameters near the noninteracting fermion limit where the charge operator dominantly couples to soliton-antisoliton pairs of the sine-Gordon model, we find that the local dynamical polarizability shows an array of sharp peaks in frequency representing coherent phase oscillations on top of an incoherent background. The strength of the coherent peaks relative to the incoherent background increases as a power law in frequency as well as exponentially as the Luttinger parameter approaches a critical value. The dynamical polarizability also clearly shows the insulating gap. We then compare the results in the high frequency limit to a perturbative estimate of phase-slip-induced decay of plasmons in the Josephson junction chain.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.99.214509}, author = {Wu, Huan-Kuang and Sau, Jay D.} } @article {ISI:000464711300007, title = {Tools for designing atom interferometers in a microgravity environment}, journal = {Phys. Rev. A}, volume = {99}, number = {4}, year = {2019}, month = {APR 15}, pages = {043615}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We present a variational model suitable for rapid preliminary design of atom interferometers in a microgravity environment. The model approximates the solution of the three-dimensional rotating-frame Gross-Pitaevskii equation as the sum of N-c Gaussian clouds. Each Gaussian cloud is assumed to have time-dependent center positions, widths, and linear and quadratic phase parameters. We applied the Lagrangian variational method (LVM) with this trial wave function to derive equations of motion for these parameters that can be adapted to any external potential. We also present a one-dimensional (1D) version of this variational model. As an example we apply the model to a 1D atom interferometry scheme for measuring Newton{\textquoteright}s gravitational constant, G, in a microgravity environment. We show how the LVM model can (1) constrain the experimental parameter space size, (2) show how the value of G can be obtained from the experimental conditions and interference pattern characteristics, and (3) show how to improve the sensitivity of the measurement and construct a preliminary error budget.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.99.043615}, author = {Ashwood, Elizabeth and Wells, Ed Wesley and Kurkcuoglu, Doga Murat and Sapp, Robert Colson and Clark, Charles W. and Edwards, Mark} } @article {ISI:000462967000001, title = {Topological bands for ultracold atoms}, journal = {Rev. Mod. Phys.}, volume = {91}, number = {1}, year = {2019}, month = {MAR 25}, pages = {015005}, publisher = {AMER PHYSICAL SOC}, type = {Review}, abstract = {There have been significant recent advances in realizing band structures with geometrical and topological features in experiments on cold atomic gases. This review summarizes these developments, beginning with a summary of the key concepts of geometry and topology for Bloch bands. Descriptions are given of the different methods that have been used to generate these novel band structures for cold atoms and of the physical observables that have allowed their characterization. The focus is on the physical principles that underlie the different experimental approaches, providing a conceptual framework within which to view these developments. Also described is how specific experimental implementations can influence physical properties. Moving beyond single-particle effects, descriptions are given of the forms of interparticle interactions that emerge when atoms are subjected to these energy bands and of some of the many-body phases that may be sought in future experiments.}, issn = {0034-6861}, doi = {10.1103/RevModPhys.91.015005}, author = {Cooper, N. R. and Dalibard, J. and Spielman, I. B.} } @article {ISI:000462967000002, title = {Topological photonics}, journal = {Rev. Mod. Phys.}, volume = {91}, number = {1}, year = {2019}, month = {MAR 25}, pages = {015006}, publisher = {AMER PHYSICAL SOC}, type = {Review}, abstract = {Topological photonics is a rapidly emerging field of research in which geometrical and topological ideas are exploited to design and control the behavior of light. Drawing inspiration from the discovery of the quantum Hall effects and topological insulators in condensed matter, recent advances have shown how to engineer analogous effects also for photons, leading to remarkable phenomena such as the robust unidirectional propagation of light, which hold great promise for applications. Thanks to the flexibility and diversity of photonics systems, this field is also opening up new opportunities to realize exotic topological models and to probe and exploit topological effects in new ways. This article reviews experimental and theoretical developments in topological photonics across a wide range of experimental platforms, including photonic crystals, waveguides, metamaterials, cavities, optomechanics, silicon photonics, and circuit QED. A discussion of how changing the dimensionality and symmetries of photonics systems has allowed for the realization of different topological phases is offered, and progress in understanding the interplay of topology with non-Hermitian effects, such as dissipation, is reviewed. As an exciting perspective, topological photonics can be combined with optical nonlinearities, leading toward new collective phenomena and novel strongly correlated states of light, such as an analog of the fractional quantum Hall effect.}, issn = {0034-6861}, doi = {10.1103/RevModPhys.91.015006}, author = {Ozawa, Tomoki and Price, Hannah M. and Amo, Alberto and Goldman, Nathan and Hafezi, Mohammad and Lu, Ling and Rechtsman, Mikael C. and Schuster, David and Simon, Jonathan and Zilberberg, Oded and Carusotto, Iacopo} } @article { ISI:000502778700003, title = {Toward convergence of effective-field-theory simulations on digital quantum computers}, journal = {Phys. Rev. A}, volume = {100}, number = {6}, year = {2019}, month = {DEC 16}, pages = {062319}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We report results for simulating an effective field theory to compute the binding energy of the deuteron nucleus using a hybrid algorithm on a trapped-ion quantum computer. Two increasingly complex unitary coupled-cluster ansatze have been used to compute the binding energy to within a few percent for successively more complex Hamiltonians. By increasing the complexity of the Hamiltonian, allowing more terms in the effective field theory expansion, and calculating their expectation values, we present a benchmark for quantum computers based on their ability to scalably calculate the effective field theory with increasing accuracy. Our result of E-4 = - 2.220 +/- 0.179 MeV may be compared with the exact deuteron ground-state energy -2.224 MeV. We also demonstrate an error mitigation technique using Richardson extrapolation on ion traps. The error mitigation circuit represents a record for deepest quantum circuit on a trapped-ion quantum computer.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.100.062319}, author = {Shehab, O. and Landsman, K. and Nam, Y. and Zhu, D. and Linke, N. M. and Keesan, M. and Pooser, R. C. and Monroe, C.} } @article { ISI:000489954500050, title = {Towards an in situ, full-power gauge of the focal-volume intensity of petawatt-class lasers}, journal = {Opt. Express}, volume = {27}, number = {21}, year = {2019}, month = {OCT 14}, pages = {30020-30030}, publisher = {OPTICAL SOC AMER}, type = {Article}, abstract = {About 50 years ago, Sarachick and Schappert {[}Phys. Rev. D. 1, 2738-2752 (1970)] showed that relativistic Thomson scattering leads to wavelength shifts that are proportional to the laser intensity. About 28 years later, Chen et al. {[}Nature 396, 653-655 (1998)] used these shifts to estimate their laser intensity near 10(18) W/cm(2). More recently, there have been several theoretical studies aimed at exploiting nonlinear Thomson scattering as a tool for direct measurement of intensities well into the relativistic regime. We present the first quantitative study of this approach for intensities between 10(18) and 10(19) W/cm(2). We show that the spectral shifts are in reasonable agreement with estimates of the peak intensity extracted from images of the focal area obtained at reduced power. Finally, we discuss the viability of the approach, its range of usefulness and how it might be extended to gauge intensities well in excess of 10(19) W/cm(2). (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement}, issn = {1094-4087}, doi = {10.1364/OE.27.030020}, author = {He, C. Z. and Longman, A. and Perez-Hernandez, J. A. and de Marco, M. and Salgado, C. and Zeraouli, G. and Gatti, G. and Roso, L. and Fedosejevs, R. and Hill, III, W. T.} } @article {ISI:000456782500003, title = {Trapped Ion Quantum Information Processing with Squeezed Phonons}, journal = {Phys. Rev. Lett.}, volume = {122}, number = {3}, year = {2019}, month = {JAN 24}, pages = {030501}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Trapped ions offer a pristine platform for quantum computation and simulation, but improving their coherence remains a crucial challenge. Here, we propose and analyze a new strategy to enhance the coherent interactions in trapped ion systems via parametric amplification of the ions{\textquoteright} motion-by squeezing the collective motional modes (phonons), the spin-spin interactions they mediate can be significantly enhanced. We illustrate the power of this approach by showing how it can enhance collective spin states useful for quantum metrology, and how it can improve the speed and fidelity of two-qubit gates in multi-ion systems, important ingredients for scalable trapped ion quantum computation. Our results are also directly relevant to numerous other physical platforms in which spin interactions are mediated by bosons.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.122.030501}, author = {Ge, Wenchao and Sawyer, Brian C. and Britton, Joseph W. and Jacobs, Kurt and Bollinger, John J. and Foss-Feig, Michael} } @article { ISI:000498896500003, title = {Tunable Quantum Beat of Single Photons Enabled by Nonlinear Nanophotonics}, journal = {Phys. Rev. Appl.}, volume = {12}, number = {5}, year = {2019}, month = {NOV 22}, pages = {054054}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We demonstrate the tunable quantum beat of single photons through the co-development of core nonlinear nanophotonic technologies for frequency-domain manipulation of quantum states in a common physical platform. Spontaneous four-wave mixing in a nonlinear resonator is used to produce nondegenerate, quantum-correlated photon pairs. One photon from each pair is then frequency shifted, without degradation of photon statistics, using four-wave-mixing Bragg scattering in a second nonlinear resonator. Fine tuning of the applied frequency shift enables tunable quantum interference of the two photons as they are impinged on a beam splitter, with an oscillating signature that depends on their frequency difference. Our work showcases the potential of nonlinear nanophotonic devices as a valuable resource for photonic quantum-information science.}, issn = {2331-7019}, doi = {10.1103/PhysRevApplied.12.054054}, author = {Li, Qing and Singh, Anshuman and Lu, Xiyuan and Lawall, John and Verma, Varun and Mirin, Richard and Nam, Sae Woo and Srinivasan, Kartik} } @article {ISI:000459152800093, title = {Twin-beam intensity-difference squeezing below 10 Hz}, journal = {Opt. Express}, volume = {27}, number = {4}, year = {2019}, month = {FEB 18}, pages = {4769-4780}, publisher = {OPTICAL SOC AMER}, type = {Article}, abstract = {We report the generation of strong, bright-beam intensity-difference squeezing down to measurement frequencies below 10 Hz. We generate two-mode squeezing in a four-wave mixing (4WM) process in Rb vapor, where the single-pass-gain nonlinear process does not require cavity locking and only relies on passive stability. We use diode laser technology and several techniques, including dual seeding, to remove the noise introduced by seeding the 4WM process as well as the background noise. Twin-beam intensity-difference squeezing down to frequencies limited only by the mechanical and atmospheric stability of the lab is achieved. These results should enable important low-frequency applications such as direct intensity-difference imaging with bright beams on integrating detectors. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement}, issn = {1094-4087}, doi = {10.1364/OE.27.004769}, author = {Wu, Meng-Chang and Schmittberger, Bonnie L. and Brewer, Nicholas R. and Speirs, Rory W. and Jones, Kevin M. and Lett, Paul D.} } @article { ISI:000489954500118, title = {Twin-beam sub-shot-noise raster-scanning microscope}, journal = {Opt. Express}, volume = {27}, number = {21}, year = {2019}, month = {OCT 14}, pages = {30810-30818}, publisher = {OPTICAL SOC AMER}, type = {Article}, abstract = {By exploiting the quantised nature of light, we demonstrate a sub-shot-noise scanning optical transmittance microscope. Our microscope demonstrates, with micron scale resolution, a factor of improvement in precision of 1.76(9) in transmittance estimation gained per probe photon relative to the theoretical model, a shot-noise-limited source of light, in an equivalent single-pass classical version of the same experiment using the same number of photons detected with a 90\% efficient detector. This would allow us to observe photosensitive samples with nearly twice the precision, without sacrificing image resolution or increasing optical power to improve signal-to-noise ratio. Our setup uses correlated twin-beams produced by parametric down-conversion, and a hybrid detection scheme comprising photon-counting-based feed-forward and a highly efficient CCD camera. Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article{\textquoteright}s title, journal citation, and DOI.}, issn = {1094-4087}, doi = {10.1364/OE.27.030810}, author = {Sabines-Chesterking, J. and McMillan, A. R. and Moreau, P. A. and Joshi, S. K. and Knauer, S. and Johnston, E. and Rarity, J. G. and Matthews, J. C. F.} } @article {ISI:000484374000010, title = {Two are better than one}, journal = {Nat. Phys.}, volume = {15}, number = {9}, year = {2019}, month = {SEP}, pages = {882-883}, publisher = {NATURE PUBLISHING GROUP}, type = {News Item}, abstract = {Two-level quantum systems are routinely excited by resonant pump beams. Experiments now show resonant excitation through dichromatic, detuned pumps - providing a coherent control technique that will also aid single-photon emission from solid-state devices.}, issn = {1745-2473}, doi = {10.1038/s41567-019-0566-9}, author = {Solomon, Glenn S.} } @article {ISI:000455163900004, title = {Two-kind boson mixture honeycomb Hamiltonian of Bloch exciton-polaritons}, journal = {Phys. Rev. B}, volume = {99}, number = {4}, year = {2019}, month = {JAN 8}, pages = {045302}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {The electronic band structure of a solid is a collection of allowed bands separated by forbidden bands, revealing the geometric symmetry of the crystal structures. Comprehensive knowledge of the band structure with band parameters explains intrinsic physical, chemical, and mechanical properties of the solid. Here we report the artificial polaritonic band structures of two-dimensional honeycomb lattices for microcavity exciton-polaritons using GaAs semiconductors in the wide-range detuning values, from cavity photonlike (red-detuned) to excitonlike (blue-detuned) regimes. In order to understand the experimental band structures and their band parameters, such as gap energies, bandwidths, hopping integrals, and density of states, we originally establish a polariton band theory within an augmented plane wave method with two-kind bosons, cavity photons trapped at the lattice sites, and freely moving excitons. In particular, this two-kind band theory is absolutely essential to elucidate the exciton effect in the band structures of blue-detuned exciton-polaritons, where the flattened excitonlike dispersion appears at larger in-plane momentum values captured in our experimental access window. We reach an excellent agreement between theory and experiments in all detuning values.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.99.045302}, author = {Pan, Haining and Winkler, K. and Powlowski, Mats and Xie, Ming and Schade, A. and Emmerling, M. and Kamp, M. and Klembt, S. and Schneider, C. and Byrnes, Tim and Hoefling, S. and Kim, Na Young} } @article { ISI:000515524300011, title = {Use of quantum effects as potential qualifying metrics for "quantum grade silicon"}, journal = {AIP Adv.}, volume = {9}, number = {12}, year = {2019}, month = {DEC 1}, pages = {125153}, publisher = {AMER INST PHYSICS}, type = {Article}, abstract = {Across solid state quantum information, material deficiencies limit performance through enhanced relaxation, charge defect motion, or isotopic spin noise. While classical measurements of device performance provide cursory guidance, specific qualifying metrics and measurements applicable to quantum devices are needed. For quantum applications, new material metrics, e.g., enrichment, are needed, while existing classical metrics such as mobility might be relaxed compared to conventional electronics. In this work, we examine locally grown silicon that is superior in enrichment, but inferior in chemical purity compared to commercial-silicon, as part of an effort to underpin the material standards needed for quantum grade silicon and establish a standard approach for the intercomparison of these materials. We use a custom, mass-selected ion beam deposition technique, which has produced isotopic enrichment levels up to 99.999 98\% Si-28, to isotopically enrich Si-28, but with chemical purity \>99.97\% due to the molecular beam epitaxy techniques used. From this epitaxial silicon, we fabricate top-gated Hall bar devices simultaneously on Si-28 and on the adjacent natural abundance Si substrate for intercomparison. Using standard-methods, we measure maximum mobilities of approximate to(1740 +/- 2) cm(2)/(V s) at an electron density of (2.7 x 10(12) +/- 3 x 10(8)) cm(-2) and approximate to(6040 +/- 3) cm(2)/(V s) at an electron density of (1.2 x 10(12) +/- 5 x 10(8)) cm(-2) at T = 1.9 K for devices fabricated on Si-28 and Si-nat, respectively. For magnetic fields B \> 2 T, both devices demonstrate well developed Shubnikov-de Haas oscillations in the longitudinal magnetoresistance. This provides the transport characteristics of isotopically enriched Si-28 and will serve as a benchmark for the classical transport of Si-28 at its current state and low temperature, epitaxially grown Si for quantum devices more generally. (C) 2019 Author(s).

}, doi = {10.1063/1.5128098}, author = {Ramanayaka, A. N. and Tang, Ke and Hagmann, J. A. and Kim, Hyun-Soo and Simons, D. S. and Richter, C. A. and Pomeroy, J. M.} } @article {14171, title = {Verified quantum information scrambling}, journal = {Nature}, year = {2019}, month = {03/2019}, doi = {10.1038/s41586-019-0952-6}, author = {Landsman, Kevin A. and Figgatt, Caroline and Schuster, T and Linke, Norbert M. and Yoshida, B and Yao, Norman Y. and Monroe, Christopher R.} } @article { ISI:000488514800006, title = {Weak Ergodicity Breaking and Quantum Many-Body Scars in Spin-1 XY Magnets}, journal = {Phys. Rev. Lett.}, volume = {123}, number = {14}, year = {2019}, month = {OCT 1}, pages = {147201}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We study the spin-1 XY model on a hypercubic lattice in d dimensions and show that this well-known nonintegrable model hosts an extensive set of anomalous finite-energy-density eigenstates with remarkable properties. Namely, they exhibit subextensive entanglement entropy and spatiotemporal long-range order, both believed to be impossible in typical highly excited eigenstates of nonintegrable quantum many-body systems. While generic initial states are expected to thermalize, we show analytically that the eigenstates we construct lead to weak crgodicity breaking in the form of persistent oscillations of local observablcs following certain quantum quenches-in other words, these eigenstates provide an archetypal example of so-called quantum many-body scars. This Letter opens the door to the analytical study of the microscopic origin, dynamical signatures, and stability of such phenomena.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.123.147201}, author = {Schecter, Michael and Iadecola, Thomas} } @article { ISI:000433962700091, title = {A 3D-printed alkali metal dispenser}, journal = {REVIEW OF SCIENTIFIC INSTRUMENTS}, volume = {89}, number = {5}, year = {2018}, month = {MAY}, pages = {056101}, issn = {0034-6748}, doi = {10.1063/1.5023906}, author = {Norrgard, E. B. and Barker, D. S. and Fedchak, J. A. and Klimov, N. and Scherschligt, J. and Eckel, S.} } @article {ISI:000423432700002, title = {Absence of thermalization in finite isolated interacting Floquet systems}, journal = {PHYSICAL REVIEW B}, volume = {97}, number = {1}, year = {2018}, month = {JAN 29}, pages = {014311}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Conventional wisdom suggests that the long-time behavior of isolated interacting periodically driven (Floquet) systems is a featureless maximal-entropy state characterized by an infinite temperature. Efforts to thwart this uninteresting fixed point include adding sufficient disorder to realize a Floquet many-body localized phase or working in a narrow region of drive frequencies to achieve glassy nonthermal behavior at long time. Here we show that in clean systems the Floquet eigenstates can exhibit nonthermal behavior due to finite system size. We consider a one-dimensional system of spinless fermions with nearest-neighbor interactions where the interaction term is driven. Interestingly, even with no static component of the interaction, the quasienergy spectrum contains gaps and a significant fraction of the Floquet eigenstates, at all quasienergies, have nonthermal average doublon densities. We show that this nonthermal behavior arises due to emergent integrability at large interaction strength and discuss how the integrability breaks down with power-law dependence on system size.}, \%\%Address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA}, issn = {2469-9950}, doi = {10.1103/PhysRevB.97.014311}, author = {Seetharam, Karthik and Titum, Paraj and Kolodrubetz, Michael and Refael, Gil} } @article { ISI:000454636100002, title = {Alkaline-Earth Atoms in Optical Tweezers}, journal = {PHYSICAL REVIEW X}, volume = {8}, number = {4}, year = {2018}, month = {DEC 28}, pages = {041055}, abstract = {We demonstrate single-shot imaging and narrow-line cooling of individual alkaline-earth atoms in optical tweezers; specifically, strontium trapped in 515.2-nm light. Our approach enables high-fidelity detection of single atoms by imaging photons from the broad singlet transition while cooling on the narrow intercombination line, and we extend this technique to highly uniform two-dimensional tweezer arrays with 121 sites. Cooling during imaging is based on a previously unobserved narrow-line Sisyphus mechanism, which we predict to be applicable in a wide variety of experimental situations. Further, we demonstrate optically resolved sideband cooling of a single atom to near the motional ground state of a tweezer, which is tuned to a magic-trapping configuration achieved by elliptical polarization. Finally, we present calculations, in agreement with our experimental results, that predict a linear-polarization and polarization-independent magic crossing at 520(2) nm and 500.65(50) nm, respectively. Our results pave the way for a wide range of novel experimental avenues based on individually controlled alkaline-earth atoms in tweezers-from fundamental experiments in atomic physics to quantum computing, simulation, and metrology.}, keywords = {Atomic and molecular physics, Quantum Information, Quantum Physics}, issn = {2160-3308}, doi = {10.1103/PhysRevX.8.041055}, author = {Cooper, Alexandre and Covey, Jacob P. and Madjarov, Ivaylo S. and Porsev, Sergey G. and Safronova, Marianna S. and Endres, Manuel} } @article { ISI:000452687700006, title = {Anomalous normal-state resistivity in superconducting La2-xCexCuO4: Fermi liquid or strange metal?}, journal = {PHYSICAL REVIEW B}, volume = {98}, number = {22}, year = {2018}, month = {DEC 10}, pages = {224503}, abstract = {We present experimental results for the in-plane resistivity of the electron-doped cuprate superconductor La2-xCexCuO4 above its transition temperature T-c as a function of Ce doping x and temperature. For the doping x between 0.11 and 0.17, where T-c varies from 30 K (x = 0.11) to 5 K (x = 0.17), we find that the resistivity shows a T-2 behavior for all values of doping over the measurement range from 70 to 250 K. The coefficient of the T-2 resistivity term decreases with increasing x following the trend in We analyze our data theoretically and posit that n-type cuprates are better thought of as strange metals. Although the quadratic temperature dependence appears to be in naive agreement with the Fermi-liquid (FL) expectations, the facts that the measured resistivity is large and approximate T-2 scattering dominates the resistivity even up to 400 K argue against a standard normal-metal FL picture being applicable. We discuss possible origins of the strange-metal behavior.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.98.224503}, author = {Sarkar, Tarapada and Greene, Richard L. and S. Das Sarma} } @article { ISI:000453488800011, title = {Atom-by-Atom Construction of a Cyclic Artificial Molecule in Silicon}, journal = {NANO LETTERS}, volume = {18}, number = {12}, year = {2018}, month = {DEC}, pages = {7502-7508}, abstract = {Hydrogen atoms on a silicon surface, H-Si (100), behave as a resist that can be patterned with perfect atomic precision using a scanning tunneling microscope. When a hydrogen atom is removed in this manner, the underlying silicon presents a chemically active site, commonly referred to as a dangling bond. It has been predicted that individual dangling bonds function as artificial atoms, which, if grouped together, can form designer molecules on the H-Si (100) surface. Here, we present an artificial ring structure molecule spanning three dimer rows, constructed from dangling bonds, and verified by spectroscopic measurement of its molecular orbitals. We found that removing 8 hydrogen atoms resulted in a molecular analog to 1,4-disilylene-hexasilabenzene (Si8H8). Scanning tunneling spectroscopic measurements reveal molecular pi and pi{*} orbitals that agree with those expected for the same molecule in a vacuum; this is validated by density functional theory calculations of the dangling bond system on a silicon slab that show direct links both to the experimental results and to calculations for the isolated molecule. We believe the unique electronic structure of artificial molecules constructed in this manner can be engineered to enable future molecule-based electronics, surface catalytic functionality, and templating for subsequent site selective deposition.}, keywords = {Artificial molecule, dangling bonds, feedback-controlled lithography, molecular orbitals}, issn = {1530-6984}, doi = {10.1021/acs.nanolett.8b02919}, author = {Wyrick, Jonathan and Wang, Xiqiao and Namboodiri, Pradeep and Schmucker, Scott W. and Kashid, Ranjit V. and Silver, Richard M.} } @article { ISI:000423426200008, title = {Atomic properties of actinide ions with particle-hole configurations}, journal = {PHYSICAL REVIEW A}, volume = {97}, number = {1}, year = {2018}, month = {JAN 25}, pages = {012511}, issn = {2469-9926}, doi = {10.1103/PhysRevA.97.012511}, author = {Safronova, M. S. and Safronova, U. I. and Kozlov, M. G.} } @article {ISI:000431374900011, title = {Beyond triplet: Unconventional superconductivity in a spin-3/2 topological semimetal}, journal = {SCIENCE ADVANCES}, volume = {4}, number = {4}, year = {2018}, month = {APR}, pages = {eaao4513}, publisher = {AMER ASSOC ADVANCEMENT SCIENCE}, type = {Article}, abstract = {In all known fermionic superfluids, Cooper pairs are composed of spin-1/2 quasi-particles that pair to formeither spinsinglet or spin-triplet bound states. The {\textquoteleft}{\textquoteleft}spin{{\textquoteright}{\textquoteright}} of a Bloch electron, however, is fixed by the symmetries of the crystal and the atomic orbitals from which it is derived and, in some cases, can behave as if it were a spin-3/2 particle. The superconducting state of such a system allows pairing beyond spin-triplet, with higher spin quasi-particles combining to formquintet or septet pairs. We report evidence of unconventional superconductivity emerging from a spin-3/2 quasi-particle electronic structure in the half-Heusler semimetal YPtBi, a low-carrier density noncentrosymmetric cubic material with a high symmetry that preserves the p-like j = 3/2 manifold in the Bi-based Gamma(8) band in the presence of strong spin-orbit coupling. With a striking linear temperature dependence of the London penetration depth, the existence of line nodes in the superconducting order parameter Delta is directly explained by a mixed-parity Cooper pairing model with high total angular momentum, consistent with a high-spin fermionic superfluid state. We propose a k.p model of the j = 3/2 fermions to explain how a dominant J = 3 septet pairing state is the simplest solution that naturally produces nodes in the mixed even-odd parity gap. Together with the underlying topologically nontrivial band structure, the unconventional pairing in this system represents a truly novel form of superfluidity that has strong potential for leading the development of a new series of topological superconductors.

}, issn = {2375-2548}, doi = {10.1126/sciadv.aao4513}, author = {Kim, Hyunsoo and Wang, Kefeng and Nakajima, Yasuyuki and Hu, Rongwei and Ziemak, Steven and Syers, Paul and Wang, Limin and Hodovanets, Halyna and Denlinger, Jonathan D. and Brydon, Philip M. R. and Agterberg, Daniel F. and Tanatar, Makariy A. and Prozorov, Ruslan and Paglione, Johnpierre} } @article { ISI:000419615700007, title = {Building topological quantum circuits: Majorana nanowire junctions}, journal = {PHYSICAL REVIEW B}, volume = {97}, number = {4}, year = {2018}, month = {JAN 9}, pages = {045410}, issn = {2469-9950}, doi = {10.1103/PhysRevB.97.045410}, author = {Stanescu, Tudor D. and S. Das Sarma} } @article { ISI:000433001000002, title = {Cavity-Enhanced Optical Readout of a Single Solid-State Spin}, journal = {PHYSICAL REVIEW APPLIED}, volume = {9}, number = {5}, year = {2018}, month = {MAY 9}, pages = {054013}, issn = {2331-7019}, doi = {10.1103/PhysRevApplied.9.054013}, author = {Sun, Shuo and Kim, Hyochul and Solomon, Glenn S. and Waks, Edo} } @article { ISI:000444740400001, title = {Challenges to miniaturizing cold atom technology for deployable vacuum metrology}, journal = {METROLOGIA}, volume = {55}, number = {5}, year = {2018}, month = {OCT}, pages = {S182-S193}, keywords = {cold atom sensing, quantum-SI, vacuum metrology}, issn = {0026-1394}, doi = {10.1088/1681-7575/aadbe4}, author = {Eckel, Stephen and Barker, Daniel S. and Fedchak, James A. and Klimov, Nikolai N. and Norrgard, Eric and Scherschligt, Julia and Makrides, Constantinos and Tiesinga, Eite} } @article { ISI:000452326000001, title = {Chiral anomaly without Landau levels: From the quantum to the classical regime}, journal = {PHYSICAL REVIEW B}, volume = {98}, number = {24}, year = {2018}, month = {DEC 6}, pages = {245109}, abstract = {We study the chiral anomaly in disordered Weyl semimetals, where the broken translational symmetry prevents the direct application of Nielsen and Ninomiya{\textquoteright}s mechanism and disorder is strong enough that quantum effects are important. In the weak disorder regime, there exist rare regions of the random potential where the disorder strength is locally strong, which gives rise to quasilocalized resonances and their effect on the chiral anomaly is unknown. We numerically show that these resonant states do not affect the chiral anomaly only in the case of a single Weyl node. At energies away from the Weyl point, or with strong disorder where one is deep in the diffusive regime, the chiral Landau level itself is not well defined and the semiclassical treatment is not justified. In this limit, we analytically use the supersymmetry method and find that the Chern-Simons term in the effective action which is not present in nontopological systems gives rise to a nonzero average level velocity which implies chiral charge pumping. We numerically establish that the nonzero average level velocity serves as an indicator of the chiral anomaly in the diffusive limit.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.98.245109}, author = {Lee, Junhyun and Pixley, J. H. and Sau, Jay D.} } @article { ISI:000445336700001, title = {Chiral Majorana fermion modes on the surface of superconducting topological insulators}, journal = {EPL}, volume = {123}, number = {4}, year = {2018}, month = {AUG}, pages = {47005}, issn = {0295-5075}, doi = {10.1209/0295-5075/123/47005}, author = {Chiu, Ching-Kai and Bian, Guang and Zheng, Hao and Yin, Jia-Xin and Zhang, Songtian S. and Sanchez, D. S. and Belopolski, I and Xu, Su-Yang and Hasan, M. Zahid} } @article { ISI:000452324400004, title = {Chiral supercurrent through a quantum Hall weak link}, journal = {PHYSICAL REVIEW B}, volume = {98}, number = {21}, year = {2018}, month = {DEC 6}, pages = {214504}, abstract = {We use an effective model to calculate properties of the supercurrent carried by chiral edge states of a quantum Hall weak link. This {\textquoteleft}{\textquoteleft}chiral{{\textquoteright}{\textquoteright}} supercurrent is qualitatively distinct from the usual Josephson supercurrent in that it cannot be mediated by a single edge alone, i.e., both right- and left-going edges are needed. Moreover, the chiral supercurrent was previously shown to obey an unusual current-phase relation with period 2 phi(0) = h/e, which is twice the period of conventional Josephson junctions. We show that the {\textquoteleft}{\textquoteleft}chiral{{\textquoteright}{\textquoteright}} nature of this supercurrent is sharply defined, and is robust to interactions to infinite order in perturbation theory. We compare our results with recent experimental findings {[}Amet et al., Science 352 966 (2016)] and find that quantitative agreement in the magnitude of the supercurrent can be attained by making reasonable but critical assumptions about the superconductor quantum Hall interface.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.98.214504}, author = {Alavirad, Yahya and Lee, Junhyun and Lin, Ze-Xun and Sau, Jay D.} } @article { ISI:000441668600006, title = {Clock-related properties of Lu+}, journal = {PHYSICAL REVIEW A}, volume = {98}, number = {2}, year = {2018}, month = {AUG 14}, pages = {022509}, issn = {2469-9926}, doi = {10.1103/PhysRevA.98.022509}, author = {Porsev, S. G. and Safronova, U. I. and Safronova, M. S.} } @article { ISI:000448933900004, title = {Collective Effects in Casimir-Polder Forces}, journal = {PHYSICAL REVIEW LETTERS}, volume = {121}, number = {18}, year = {2018}, month = {NOV 1}, pages = {183605}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.121.183605}, author = {Sinha, Kanupriya and Venkatesh, B. Prasanna and Meystre, Pierre} } @article { ISI:000423428400002, title = {Conductance interference in a superconducting Coulomb blockaded Majorana ring}, journal = {PHYSICAL REVIEW B}, volume = {97}, number = {3}, year = {2018}, month = {JAN 26}, pages = {035310}, issn = {2469-9950}, doi = {10.1103/PhysRevB.97.035310}, author = {Chiu, Ching-Kai and Sau, Jay D. and S. Das Sarma} } @article { ISI:000449292600001, title = {Configuration-controlled many-body localization and the mobility emulsion}, journal = {PHYSICAL REVIEW B}, volume = {98}, number = {17}, year = {2018}, month = {NOV 2}, pages = {174201}, issn = {2469-9950}, doi = {10.1103/PhysRevB.98.174201}, author = {Schecter, Michael and Iadecola, Thomas and S. Das Sarma} } @article { ISI:000432031700004, title = {Cooper pair induced frustration and nematicity of two-dimensional magnetic adatom lattices}, journal = {PHYSICAL REVIEW B}, volume = {97}, number = {17}, year = {2018}, month = {MAY 10}, pages = {174412}, issn = {2469-9950}, doi = {10.1103/PhysRevB.97.174412}, author = {Schecter, Michael and Syljuasen, Olav F. and Paaske, Jens} } @article {9151, title = {Dark State Optical Lattice with a Subwavelength Spatial Structure}, journal = {Phys. Rev. Lett.}, volume = {120}, year = {2018}, month = {Feb}, pages = {083601}, doi = {10.1103/PhysRevLett.120.083601}, url = {https://link.aps.org/doi/10.1103/PhysRevLett.120.083601}, author = {Wang, Y. and Subhankar, S. and Bienias, P and {\L}{\k a}cki, M. and Tsui, T-C. and Baranov, M. A. and Gorshkov, A. V. and Zoller, P. and Porto, J. V. and Rolston, S. L.} } @article { ISI:000439334800001, title = {Demonstration of a Bayesian quantum game on an ion-trap quantum computer}, journal = {QUANTUM SCIENCE AND TECHNOLOGY}, volume = {3}, number = {4}, year = {2018}, month = {OCT}, pages = {UNSP 045002}, keywords = {ion traps, quantum computation, quantum games}, issn = {2058-9565}, doi = {10.1088/2058-9565/aacf0e}, author = {Solmeyer, Neal and Linke, Norbert M. and Figgatt, Caroline and Landsman, Kevin A. and Balu, Radhakrishnan and Siopsis, George and Monroe, C.} } @article { ISI:000429937300002, title = {Demonstration of Protection of a Superconducting Qubit from Energy Decay}, journal = {PHYSICAL REVIEW LETTERS}, volume = {120}, number = {15}, year = {2018}, month = {APR 13}, pages = {150503}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.120.150503}, author = {Lin, Yen-Hsiang and Nguyen, Long B. and Grabon, Nicholas and San Miguel, Jonathan and Pankratova, Natalia and Manucharyan, Vladimir E.} } @article {ISI:000427010500002, title = {Disorder-induced half-integer quantized conductance plateau in quantum anomalous Hall insulator-superconductor structures}, journal = {PHYSICAL REVIEW B}, volume = {97}, number = {10}, year = {2018}, month = {MAR 9}, pages = {100501}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {A weak superconducting proximity effect in the vicinity of the topological transition of a quantum anomalous Hall system has been proposed as a venue to realize a topological superconductor (TSC) with chiral Majorana edge modes (CMEMs). A recent experiment {[}Science 357, 294 (2017)] claimed to have observed such CMEMs in the form of a half-integer quantized conductance plateau in the two-terminal transport measurement of a quantum anomalous Hall-superconductor junction. Although the presence of a superconducting proximity effect generically splits the quantum Hall transition into two phase transitions with a gapped TSC in between, in this Rapid Communication we propose that a nearly flat conductance plateau, similar to that expected from CMEMs, can also arise from the percolation of quantum Hall edges well before the onset of the TSC or at temperatures much above the TSC gap. Our Rapid Communication, therefore, suggests that, in order to confirm the TSC, it is necessary to supplement the observation of the half-quantized conductance plateau with a hard superconducting gap (which is unlikely for a disordered system) from the conductance measurements or the heat transport measurement of the transport gap. Alternatively, the half-quantized thermal conductance would also serve as a smoking-gun signature of the TSC.}, \%\%Address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA}, issn = {2469-9950}, doi = {10.1103/PhysRevB.97.100501}, author = {Huang, Yingyi and Setiawan, F. and Sau, Jay D.} } @article { ISI:000444557300003, title = {Dissipation-enabled fractional Josephson effect}, journal = {PHYSICAL REVIEW B}, volume = {98}, number = {12}, year = {2018}, month = {SEP 12}, pages = {125124}, issn = {2469-9950}, doi = {10.1103/PhysRevB.98.125124}, author = {Sticlet, Doru and Sau, Jay D. and Akhmerov, Anton} } @article { ISI:000434209100002, title = {Distinguishing topological Majorana bound states from trivial Andreev bound states: Proposed tests through differential tunneling conductance spectroscopy}, journal = {PHYSICAL REVIEW B}, volume = {97}, number = {21}, year = {2018}, month = {JUN 5}, pages = {214502}, issn = {2469-9950}, doi = {10.1103/PhysRevB.97.214502}, author = {Liu, Chun-Xiao and Sau, Jay D. and S. Das Sarma} } @article { ISI:000419476900017, title = {Dressed infrared quantum information}, journal = {PHYSICAL REVIEW D}, volume = {97}, number = {2}, year = {2018}, month = {JAN 8}, pages = {025007}, issn = {2470-0010}, doi = {10.1103/PhysRevD.97.025007}, author = {Carney, Daniel and Chaurette, Laurent and Neuenfeld, Dominik and Semenoff, Gordon Walter} } @article {10476, title = {Dynamo Effect and Turbulence in Hydrodynamic Weyl Metals}, journal = {Phys. Rev. Lett.}, volume = {121}, year = {2018}, month = {Oct}, pages = {176603}, doi = {10.1103/PhysRevLett.121.176603}, url = {https://link.aps.org/doi/10.1103/PhysRevLett.121.176603}, author = {Galitski, Victor and Kargarian, Mehdi and Syzranov, Sergey} } @article { ISI:000447148100009, title = {Effect of device design on charge offset drift in Si/SiO2 single electron devices}, journal = {JOURNAL OF APPLIED PHYSICS}, volume = {124}, number = {14}, year = {2018}, month = {OCT 14}, pages = {144302}, issn = {0021-8979}, doi = {10.1063/1.5048013}, author = {Hu, Binhui and Ochoa, Erick D. and Sanchez, Daniel and Perron, Justin K. and Zimmerman, Neil M. and Stewart, Jr., M. D.} } @article { ISI:000439543800001, title = {Effective theory approach to the Schrodinger-Poisson problem in semiconductor Majorana devices}, journal = {PHYSICAL REVIEW B}, volume = {98}, number = {3}, year = {2018}, month = {JUL 24}, pages = {035428}, issn = {2469-9950}, doi = {10.1103/PhysRevB.98.035428}, author = {Woods, Benjamin D. and Stanescu, Tudor D. and S. Das Sarma} } @article {ISI:000430601100005, title = {Effects of resonant-laser excitation on the emission properties in a single quantum dot}, journal = {OPTICA}, volume = {5}, number = {4}, year = {2018}, month = {APR 20}, pages = {354-359}, publisher = {OPTICAL SOC AMER}, type = {Article}, abstract = {While many solid-state emitters can be optically excited non-resonantly, resonant excitation is necessary for many quantum information protocols as it often maximizes the non-classicality of the emitted light. Here, we study the resonance fluorescence in a solid-state system-a quantum dot-with the addition of weak, non-resonant light. In the inelastic scattering regime, changes in the resonance fluorescence intensity and linewidth are linked to both the non-resonant and resonant laser powers. Details of the intensity change indicate that charge-carrier loss from the quantum dot is resonant laser. As we enter the Mollow triplet regime, this resonant laser loss term rate is approximately 1/50 ns(-1). This work further clarifies resonance fluorescence in solid-state systems and will aid in the further improvement of solid-state non-classical light sources.}, \%\%Address = {2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA}, issn = {2334-2536}, doi = {10.1364/OPTICA.5.000354}, author = {Gazzano, O. and Huber, T. and Loo, V and Polyakov, S. and Flagg, E. B. and Solomon, G. S.} } @article { ISI:000447310800001, title = {Electrooptomechanical Equivalent Circuits for Quantum Transduction}, journal = {PHYSICAL REVIEW APPLIED}, volume = {10}, number = {4}, year = {2018}, month = {OCT 15}, pages = {044036}, issn = {2331-7019}, doi = {10.1103/PhysRevApplied.10.044036}, author = {Zeuthen, Emil and Schliesser, Albert and Taylor, Jacob M. and Sorensen, Anders S.} } @article { ISI:000451073900001, title = {Equations of state from individual one-dimensional Bose gases}, journal = {NEW JOURNAL OF PHYSICS}, volume = {20}, year = {2018}, month = {NOV 23}, pages = {113032}, abstract = {We trap individual 1D Bose gases and obtain the associated equation of state by combining calibrated confining potentials with in situ density profiles. Our observations agree well with the exact Yang- Yang 1D thermodynamic solutions under the local density approximation. We find that our final 1D system undergoes inefficient evaporative cooling that decreases the absolute temperature, but monotonically reduces a degeneracy parameter.}, keywords = {atomic physics, equation of state, one-dimensonal Bose gas, quantum gases}, issn = {1367-2630}, doi = {10.1088/1367-2630/aaef9b}, author = {Salces-Carcoba, F. and Billington, C. J. and Putra, A. and Yue, Y. and Sugawa, S. and Ian B Spielman} } @article { ISI:000448756700003, title = {Generation of a Lattice of Spin-Orbit Beams via Coherent Averaging}, journal = {PHYSICAL REVIEW LETTERS}, volume = {121}, number = {18}, year = {2018}, month = {OCT 30}, pages = {183602}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.121.183602}, author = {Sarenac, D. and Cory, D. G. and Nsofini, J. and Hincks, I. and Miguel, P. and Arif, M. and Clark, Charles W. and Huber, M. G. and Pushin, D. A.} } @article { ISI:000448973100018, title = {Giant anomalous Nernst effect and quantum-critical scaling in a ferromagnetic semimetal}, journal = {NATURE PHYSICS}, volume = {14}, number = {11}, year = {2018}, month = {NOV}, pages = {1119+}, issn = {1745-2473}, doi = {10.1038/s41567-018-0225-6}, author = {Sakai, Akito and Mizuta, Yo Pierre and Nugroho, Agustinus Agung and Sihombing, Rombang and Koretsune, Takashi and Suzuki, Michi-To and Takemori, Nayuta and Ishii, Rieko and Nishio-Hamane, Daisuke and Arita, Ryotaro and Goswami, Pallab and Nakatsuji, Satoru} } @article { ISI:000441010300002, title = {Global phase diagram and momentum distribution of single-particle excitations in Kondo insulators}, journal = {PHYSICAL REVIEW B}, volume = {98}, number = {8}, year = {2018}, month = {AUG 7}, pages = {085110}, issn = {2469-9950}, doi = {10.1103/PhysRevB.98.085110}, author = {Pixley, J. H. and Yu, Rong and Paschen, Silke and Si, Qimiao} } @article { ISI:000445057800002, title = {Global Phase Diagram of a Dirty Weyl Liquid and Emergent Superuniversality}, journal = {PHYSICAL REVIEW X}, volume = {8}, number = {3}, year = {2018}, month = {SEP 19}, pages = {031076}, issn = {2160-3308}, doi = {10.1103/PhysRevX.8.031076}, author = {Roy, Bitan and Slager, Robert-Jan and Juricic, Vladimir} } @article {ISI:000428598700001, title = {Hardware-efficient fermionic simulation with a cavity-QED system}, journal = {NPJ QUANTUM INFORMATION}, volume = {4}, year = {2018}, month = {FEB 27}, pages = {16}, publisher = {NATURE PUBLISHING GROUP}, type = {Article}, abstract = {In digital quantum simulation of fermionic models with qubits, non-local maps for encoding are often encountered. Such maps require linear or logarithmic overhead in circuit depth which could render the simulation useless, for a given decoherence time. Here we show how one can use a cavity-QED system to perform digital quantum simulation of fermionic models. In particular, we show that highly nonlocal Jordan-Wigner or Bravyi-Kitaev transformations can be efficiently implemented through a hardware approach. The key idea is using ancilla cavity modes, which are dispersively coupled to a qubit string, to collectively manipulate and measure qubit states. Our scheme reduces the circuit depth in each Trotter step of the Jordan-Wigner encoding by a factor of N-2, comparing to the scheme for a device with only local connectivity, where N is the number of orbitals for a generic two-body Hamiltonian. Additional analysis for the Fermi-Hubbard model on an N x N square lattice results in a similar reduction. We also discuss a detailed implementation of our scheme with superconducting qubits and cavities.}, \%\%Address = {MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND}, issn = {2056-6387}, doi = {10.1038/s41534-018-0065-3}, author = {Zhu, Guanyu and Subasi, Yigit and Whitfield, James D. and Hafezi, Mohammad} } @inbook { ISI:000429191300003, title = {High-Dimensional Disorder-Driven Phenomena in Weyl Semimetals, Semiconductors, and Related Systems}, booktitle = {ANNUAL REVIEW OF CONDENSED MATTER PHYSICS, VOL 9}, series = {Annual Review of Condensed Matter Physics}, volume = {9}, year = {2018}, pages = {35-58}, keywords = {Dirac semimetals, disordered systems, localization, phase transitions}, issn = {1947-5454}, doi = {10.1146/annurev-conmatphys-033117-054037}, author = {Syzranov, Sergey V. and Radzihovsky, Leo}, editor = {Sachdev, S and Marchetti, MC} } @article { ISI:000425091300007, title = {High-fidelity quantum gates in Si/SiGe double quantum dots}, journal = {PHYSICAL REVIEW B}, volume = {97}, number = {8}, year = {2018}, month = {FEB 15}, pages = {085421}, issn = {2469-9950}, doi = {10.1103/PhysRevB.97.085421}, author = {Russ, Maximilian and Zajac, D. M. and Sigillito, A. J. and Borjans, F. and Taylor, J. M. and Petta, J. R. and Burkard, Guido} } @article { ISI:000451992400001, title = {Highly charged ions: Optical clocks and applications in fundamental physics}, journal = {REVIEWS OF MODERN PHYSICS}, volume = {90}, number = {4}, year = {2018}, month = {DEC 4}, pages = {045005}, abstract = {Recent developments in frequency metrology and optical clocks have been based on electronic transitions in atoms and singly charged ions as references. The control over all relevant degrees of freedom in these atoms has enabled relative frequency uncertainties at a level of 10(-18). This accomplishment not only allows for extremely accurate time and frequency measurements, but also to probe our understanding of fundamental physics, such as a possible variation of fundamental constants, a violation of the local Lorentz invariance, and the existence of forces beyond the standard model of physics. In addition, novel clocks are driving the development of sophisticated technical applications. Crucial for applications of clocks in fundamental physics are a high sensitivity to effects beyond the standard model and a small frequency uncertainty of the clock. Highly charged ions offer both. They possess optical transitions which can be extremely narrow and less sensitive to external perturbations compared to current atomic clock species. The large selection of highly charged ions offers narrow transitions that are among the most sensitive ones for the {\textquoteleft}{\textquoteleft}new physics{{\textquoteright}{\textquoteright}} effects. Recent experimental advances in trapping and sympathetic cooling of highly charged ions will in the future enable advanced quantum logic techniques for controlling motional and internal degrees of freedom and thus enable high-accuracy optical spectroscopy. Theoretical progress in calculating the properties of selected highly charged ions has allowed the evaluation of systematic shifts and the prediction of the sensitivity to the physics beyond the standard model. New theoretical challenges and opportunities emerge from relativistic, quantum electrodynamics, and nuclear-size contributions that become comparable with interelectronic correlations. This article reviews the current status of the field, addresses specific electronic configurations and systems which show the most promising properties for research, their potential limitations, and the techniques for their study.}, issn = {0034-6861}, doi = {10.1103/RevModPhys.90.045005}, author = {Kozlov, M. G. and Safronova, M. S. and Lopez-Urrutia, J. R. Crespo and Schmidt, P. O.} } @article { ISI:000425089500005, title = {High-precision measurements and theoretical calculations of indium excited-state polarizabilities}, journal = {PHYSICAL REVIEW A}, volume = {97}, number = {2}, year = {2018}, month = {FEB 15}, pages = {022507}, issn = {2469-9926}, doi = {10.1103/PhysRevA.97.022507}, author = {Vilas, N. B. and Wang, B. -Y. and Rupasinghe, P. M. and Maser, D. L. and Safronova, M. S. and Safronova, U. I. and Majumder, P. K.} } @article { ISI:000447148100013, title = {Long spin-flip time and large Zeeman splitting of holes in type-II ZnTe/ZnSe submonolayer quantum dots}, journal = {JOURNAL OF APPLIED PHYSICS}, volume = {124}, number = {14}, year = {2018}, month = {OCT 14}, pages = {144306}, issn = {0021-8979}, doi = {10.1063/1.5041478}, author = {Ji, H. and Dhomkar, S. and Wu, R. and Ludwig, J. and Lu, Z. and Smirnov, D. and Tamargo, M. C. and Bryant, G. W. and Kuskovsky, I. L.} } @article { ISI:000442340900001, title = {Machine learning assisted readout of trapped-ion qubits}, journal = {JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS}, volume = {51}, number = {17}, year = {2018}, month = {SEP 14}, pages = {174006}, keywords = {ion traps, machine learning, quantum computing}, issn = {0953-4075}, doi = {10.1088/1361-6455/aad62b}, author = {Seif, Alireza and Landsman, Kevin A. and Linke, Norbert M. and Figgatt, Caroline and Monroe, C. and Hafezi, Mohammad} } @article { ISI:000439729800001, title = {Many-body spectral reflection symmetry and protected infinite-temperature degeneracy}, journal = {PHYSICAL REVIEW B}, volume = {98}, number = {3}, year = {2018}, month = {JUL 25}, pages = {035139}, issn = {2469-9950}, doi = {10.1103/PhysRevB.98.035139}, author = {Schecter, Michael and Iadecola, Thomas} } @article { ISI:000418495400015, title = {Measurements of enthalpy of sublimation of Ne, N-2, O-2, Ar, CO2, Kr, Xe, and H2O using a double paddle oscillator}, journal = {JOURNAL OF CHEMICAL THERMODYNAMICS}, volume = {118}, year = {2018}, month = {MAR}, pages = {127-138}, keywords = {Argon, Carbon dioxide, Double paddle oscillator, Enthalpy of sublimation, Krypton, Neon, Nitrogen, Oxygen, Xenon and water}, issn = {0021-9614}, doi = {10.1016/j.jct.2017.11.004}, author = {Shakeel, Hamza and Wei, Haoyan and Pomeroy, J. M.} } @article { ISI:000447297200006, title = {Metamorphosis of Andreev bound states into Majorana bound states in pristine nanowires}, journal = {PHYSICAL REVIEW B}, volume = {98}, number = {14}, year = {2018}, month = {OCT 15}, pages = {144511}, issn = {2469-9950}, doi = {10.1103/PhysRevB.98.144511}, author = {Huang, Yingyi and Pan, Haining and Liu, Chun-Xiao and Sau, Jay D. and Stanescu, Tudor D. and S. Das Sarma} } @article { ISI:000447077700007, title = {Methods for preparation and detection of neutron spin-orbit states}, journal = {NEW JOURNAL OF PHYSICS}, volume = {20}, year = {2018}, month = {OCT 10}, pages = {103012}, keywords = {neutron optics, orbital angular momentum, spin-orbit states}, issn = {1367-2630}, doi = {10.1088/1367-2630/aae3ac}, author = {Sarenac, D. and Nsofini, J. and Hincks, I. and Arif, M. and Clark, Charles W. and Cory, D. G. and Huber, M. G. and Pushin, D. A.} } @article { ISI:000424507800014, title = {Multipolar Polarizabilities and Hyperpolarizabilities in the Sr Optical Lattice Clock}, journal = {PHYSICAL REVIEW LETTERS}, volume = {120}, number = {6}, year = {2018}, month = {FEB 8}, pages = {063204}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.120.063204}, author = {Porsev, S. G. and Safronova, M. S. and Safronova, U. I. and Kozlov, M. G.} } @article { ISI:000445109300001, title = {On the need for soft dressing}, journal = {JOURNAL OF HIGH ENERGY PHYSICS}, number = {9}, year = {2018}, month = {SEP 20}, pages = {121}, keywords = {Effective Field Theories, Gauge Symmetry, Scattering Amplitudes, Space-Time Symmetries}, issn = {1029-8479}, doi = {10.1007/JHEP09(2018)121}, author = {Carney, Daniel and Chaurette, Laurent and Neuenfeld, Dominik and Semenoff, Gordon} } @article { ISI:000427007200003, title = {New Methods for Testing Lorentz Invariance with Atomic Systems}, journal = {PHYSICAL REVIEW LETTERS}, volume = {120}, number = {10}, year = {2018}, month = {MAR 8}, pages = {103202}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.120.103202}, author = {Shaniv, R. and Ozeri, R. and Safronova, M. S. and Porsev, S. G. and Dzuba, V. A. and flambaum, v. v. and Haffner, H.} } @conference { ISI:000450231900351, title = {NIST Kibble balance performance}, booktitle = {2018 CONFERENCE ON PRECISION ELECTROMAGNETIC MEASUREMENTS (CPEM 2018)}, year = {2018}, note = {Conference on Precision Electromagnetic Measurements (CPEM), Paris, FRANCE, JUL 08-13, 2018}, keywords = {Kibble balance, mass metrology, Planck constant, redefinition of the SI}, isbn = {978-1-5386-0974-3}, author = {Seifert, F. and Haddad, D. and Chao, L. S. and Newell, D. B. and Pratt, J. R. and Williams, C. and Schlamminger, S.} } @article { ISI:000451329500021, title = {Nobelium energy levels and hyperfine-structure constants}, journal = {PHYSICAL REVIEW A}, volume = {98}, number = {5}, year = {2018}, month = {NOV 26}, pages = {052512}, abstract = {Advances in laser spectroscopy of superheavy (Z > 100) elements enabled determination of the nuclear moments of the heaviest nuclear which required high-precision atomic calculations of the relevant hyperfine-structure (hfs) constants. Here, we calculated the hfs constants and energy levels for a number of nobelium (Z = 102) states using a hybrid approach combining linearized coupled-cluster and configuration interaction methods. We also carried out an extensive study of the No energies using the 16-electro configuration interaction method to determine the position of the 5f(13)7s(2)6d and 5f(13)7s(2)7p levels with a hole in the 5 f shell to evaluate their potential effect on the hyperfine-structure calculations of the low-lying 5f(14)7s6d and 5f(14)7s7p levels. We find that unlike the case of Yb, the mixing of the low-lying levels with filled and unfilled f shells is small and does not significantly influence their properties. The resulting hfs constants for the 5f(14)7s7p P-1(1)0 level, combined with laser-spectroscopy measurement, were used to extract nobelium nuclear properties.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.98.052512}, author = {Porsev, S. G. and Safronova, M. S. and Safronova, I, U. and Dzuba, V. A. and flambaum, v. v.} } @article { ISI:000451010600006, title = {Nuclear Charge Radii of Th-229 from Isotope and Isomer Shifts}, journal = {PHYSICAL REVIEW LETTERS}, volume = {121}, number = {21}, year = {2018}, month = {NOV 21}, pages = {213001}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.121.213001}, author = {Safronova, M. S. and Porsev, S. G. and Kozlov, M. G. and Thielking, J. and Okhapkin, M. V. and Glowacki, P. and Meier, D. M. and Peik, E.} } @article { ISI:000419549600036, title = {Optimized phase sensing in a truncated SU(1,1) interferometer}, journal = {OPTICS EXPRESS}, volume = {26}, number = {1}, year = {2018}, month = {JAN 8}, pages = {391-401}, issn = {1094-4087}, doi = {10.1364/OE.26.000391}, author = {Gupta, Prasoon and Schmittberger, Bonnie L. and Anderson, Brian E. and Jones, Kevin M. and Lett, Paul D.} } @article {ISI:000430909100001, title = {Out-of-time-order correlators in finite open systems}, journal = {PHYSICAL REVIEW B}, volume = {97}, number = {16}, year = {2018}, month = {APR 26}, pages = {161114}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We study out-of-time-order correlators (OTOCs) of the form <(A) over cap (t) (B) over cap (0) (C) over cap (t) (D) over cap (0)> for a quantum system weakly coupled to a dissipative environment. Such an open system may serve as a model of, e. g., a small region in a disordered interacting medium coupled to the rest of this medium considered as an environment. We demonstrate that for a system with discrete energy levels the OTOC saturates exponentially alpha Sigma a(i)e(-t/tau i) + const to a constant value at t -> infinity, in contrast with quantum-chaotic systemswhich exhibit exponential growth of OTOCs. Focusing on the case of a two-level system, we calculate microscopically the decay times tau(i) and the value of the saturation constant. Because some OTOCs are immune to dephasing processes and some are not, such correlators may decay on two sets of parametrically different time scales related to inelastic transitions between the system levels and to pure dephasing processes, respectively. In the case of a classical environment, the evolution of the OTOC can be mapped onto the evolution of the density matrix of two systems coupled to the same dissipative environment.}, \%\%Address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA}, issn = {2469-9950}, doi = {10.1103/PhysRevB.97.161114}, author = {Syzranov, S. V. and Gorshkov, A. V. and Galitski, V.} } @article { ISI:000436968900002, title = {Perpetual emulation threshold of PT-symmetric Hamiltonians}, journal = {JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL}, volume = {51}, number = {32}, year = {2018}, month = {AUG 10}, pages = {325302}, keywords = {non-Hermitian, pseudospins, PT-symmetry}, issn = {1751-8113}, doi = {10.1088/1751-8121/aacc5e}, author = {Trypogeorgos, D. and Valdes-Curiell, A. and Ian B Spielman and Emary, C.} } @article { ISI:000443395300001, title = {Phonon-induced Majorana qubit relaxation in tunnel-coupled two-island topological superconductors}, journal = {PHYSICAL REVIEW B}, volume = {98}, number = {7}, year = {2018}, month = {AUG 31}, pages = {075159}, issn = {2469-9950}, doi = {10.1103/PhysRevB.98.075159}, author = {Song, Yang and S. Das Sarma} } @article { ISI:000442483400036, title = {Photonic topological Anderson insulators}, journal = {NATURE}, volume = {560}, number = {7719}, year = {2018}, month = {AUG 23}, pages = {461+}, issn = {0028-0836}, doi = {10.1038/s41586-018-0418-2}, author = {Stutzer, Simon and Plotnik, Yonatan and Lumer, Yaakov and Titum, Paraj and Lindner, Netanel H. and Segev, Mordechai and Rechtsman, Mikael C. and Szameit, Alexander} } @article {ISI:000423393300009, title = {Probe Knots and Hopf Insulators with Ultracold Atoms}, journal = {CHINESE PHYSICS LETTERS}, volume = {35}, number = {1}, year = {2018}, month = {JAN}, pages = {013701}, publisher = {IOP PUBLISHING LTD}, type = {Article}, abstract = {Knots and links are fascinating and intricate topological objects. Their influence spans from DNA and molecular chemistry to vortices in superfluid helium, defects in liquid crystals and cosmic strings in the early universe. Here we find that knotted structures also exist in a peculiar class of three-dimensional topological insulators-the Hopf insulators. In particular, we demonstrate that the momentum-space spin textures of Hopf insulators are twisted in a nontrivial way, which implies the presence of various knot and link structures. We further illustrate that the knots and nontrivial spin textures can be probed via standard time-of-flight images in cold atoms as preimage contours of spin orientations in stereographic coordinates. The extracted Hopf invariants, knots, and links are validated to be robust to typical experimental imperfections. Our work establishes the existence of knotted structures in Hopf insulators, which may have potential applications in spintronics and quantum information processing.}, \%\%Address = {TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND}, issn = {0256-307X}, doi = {10.1088/0256-307X/35/1/013701}, author = {Deng, Dong-Ling and Wang, Sheng-Tao and Sun, Kai and Duan, L. -M.} } @article { ISI:000434633000006, title = {Probing Sizes and Shapes of Nobelium Isotopes by Laser Spectroscopy}, journal = {PHYSICAL REVIEW LETTERS}, volume = {120}, number = {23}, year = {2018}, month = {JUN 8}, pages = {232503}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.120.232503}, author = {Raeder, S. and Ackermann, D. and Backe, H. and Beerwerth, R. and Berengut, J. C. and Block, M. and Borschevsky, A. and Cheal, B. and Chhetri, P. and Duellmann, Ch. E. and Dzuba, V. A. and Eliav, E. and Even, J. and Ferrer, R. and flambaum, v. v. and Fritzsche, S. and Giacoppo, F. and Goetz, S. and Hessberger, F. P. and Huyse, M. and Kaldor, U. and Kaleja, O. and Khuyagbaatar, J. and Kunz, P. and Laatiaoui, M. and Lautenschlager, F. and Lauth, W. and Mistry, A. K. and Ramirez, E. Minaya and Nazarewicz, W. and Porsev, S. G. and Safronova, M. S. and Safronova, U. I. and Schuetrumpf, B. and Van Duppen, P. and Walther, T. and Wraith, C. and Yakushev, A.} } @article {9191, title = {Quantized Majorana conductance}, journal = {Nature}, volume = {Advanced Online Publication}, year = {2018}, month = {03/2018}, url = {http://dx.doi.org/10.1038/nature26142}, author = {Zhang, Hao and Liu, Chun-Xiao and Gazibegovic, Sasa and Xu, Di and Logan, John A. and Wang, Guanzhong and van Loo, Nick and Bommer, Jouri D. S. and de Moor, Michiel W. A. and Car, Diana and Op het Veld, Roy L. M. and van Veldhoven, Petrus J. and Koelling, Sebastian and Verheijen, Marcel A. and Pendharkar, Mihir and Pennachio, Daniel J. and Shojaei, Borzoyeh and Lee, Joon Sue and Palmstr{\o}m, Chris J. and Bakkers, Erik P. A. M. and S. Das Sarma and Kouwenhoven, Leo P.} } @article { ISI:000449780400004, title = {Quantum field theory for the chiral clock transition in one spatial dimension}, journal = {PHYSICAL REVIEW B}, volume = {98}, number = {20}, year = {2018}, month = {NOV 9}, pages = {205118}, issn = {2469-9950}, doi = {10.1103/PhysRevB.98.205118}, author = {Whitsitt, Seth and Samajdar, Rhine and Sachdev, Subir} } @article { ISI:000447918000003, title = {Quantum inverse freezing and mirror-glass order}, journal = {PHYSICAL REVIEW B}, volume = {98}, number = {14}, year = {2018}, month = {OCT 22}, pages = {144204}, issn = {2469-9950}, doi = {10.1103/PhysRevB.98.144204}, author = {Iadecola, Thomas and Schecter, Michael} } @article { ISI:000423237900002, title = {Quantum thermodynamics from the nonequilibrium dynamics of open systems: Energy, heat capacity, and the third law}, journal = {PHYSICAL REVIEW E}, volume = {97}, number = {1}, year = {2018}, month = {JAN 23}, pages = {012135}, issn = {2470-0045}, doi = {10.1103/PhysRevE.97.012135}, author = {Hsiang, J. -T. and Chou, C. H. and Subasi, Y. and Hu, B. L.} } @article { ISI:000454161400003, title = {Quasiparticle gaps in multiprobe Majorana nanowires}, journal = {PHYSICAL REVIEW B}, volume = {98}, number = {22}, year = {2018}, month = {DEC 18}, pages = {224512}, abstract = {We theoretically study a spin-orbit-coupled nanowire proximitized by a superconductor in the presence of an externally applied Zeeman field ({{\textquoteright}{\textquoteright}}Majorana nanowire{{\textquoteright}{\textquoteright}}) with zero-energy Majorana bound states localized at the two ends of the wire when the Zeeman spin splitting is large enough for the system to enter the topological phase. The specific physics of interest in the current work is the effect of having several tunnel probes attached to the wire along its length. Such tunnel probes should allow, as a matter of principle, one to observe both the predicted bulk superconducting gap closing and opening associated with the topological quantum phase transition as well as the Majorana bound states at the wire ends showing up as zero-bias conductance peaks, depending on which probes are used for the tunneling spectroscopy measurement. Because of the possible invasive nature of the tunnel probes, producing local potential fluctuations in the nanowire, we find the physical situation to be quite complex. In particular, depending on the details of the tunnel barrier operational at the probes, the Majorana nanowire could manifest additional low-energy Andreev bound states which will manifest their own almost-zero-bias peaks, complicating the interpretation of the tunneling data in multiprobe Majorana nanowires. We use two complementary microscopic models to simulate the probes, finding that the tunneling conductance spectrum depends rather sensitively on the details of the tunnel barriers at the probes, but in some situations it should be possible to observe the Majorana bound-state-induced zero-bias conductance peak at the wire ends along with the gap closing and opening features associated with the bulk topological quantum phase transition in the multiprobe Majorana nanowires. Our detailed numerical results indicate that such a system should also be capable of directly manifesting the nonlocal conductance correlations arising from Majorana bound states at the two ends of the nanowire. We apply our general analysis to simulate a recent multiprobe nanowire experiment commenting on the nature of the quasiparticle gaps likely controlling the experimental observations.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.98.224512}, author = {Huang, Yingyi and Sau, Jay D. and Stanescu, Tudor D. and S. Das Sarma} } @article {9246, title = {A Rapidly Expanding Bose-Einstein Condensate: An Expanding Universe in the Lab}, journal = {Phys. Rev. X}, volume = {8}, year = {2018}, month = {Apr}, pages = {021021}, doi = {10.1103/PhysRevX.8.021021}, url = {https://link.aps.org/doi/10.1103/PhysRevX.8.021021}, author = {Eckel, S and Kumar, A and Jacobson, T and Ian B Spielman and Campbell, G K} } @article { ISI:000419097100004, title = {Relativistic all-order many-body calculation of energies, wavelengths, and M1 and E2 transition rates for the 3d(n) configurations in tungsten ions}, journal = {PHYSICAL REVIEW A}, volume = {97}, number = {1}, year = {2018}, month = {JAN 3}, pages = {012502}, issn = {2469-9926}, doi = {10.1103/PhysRevA.97.012502}, author = {Safronova, M. S. and Safronova, U. I. and Porsev, S. G. and Kozlov, M. G. and Ralchenko, Yu.} } @article { ISI:000423283200042, title = {Resonantly driven CNOT gate for electron spins}, journal = {SCIENCE}, volume = {359}, number = {6374}, year = {2018}, month = {JAN 26}, pages = {439-442}, issn = {0036-8075}, doi = {10.1126/science.aao5965}, author = {Zajac, D. M. and Sigillito, A. J. and Russ, M. and Borjans, F. and Taylor, J. M. and Burkard, G. and Petta, J. R.} } @conference { ISI:000455155000056, title = {Scalable quantum photonics using quantum dots}, booktitle = {2018 IEEE PHOTONICS SOCIETY SUMMER TOPICAL MEETING SERIES (SUM)}, year = {2018}, note = {IEEE Photonics Society Summer Topical Meeting Series (SUM), Waikoloa Village, HI, JUL 09-11, 2018}, pages = {129-130}, isbn = {978-1-5386-5343-2}, author = {Waks, Edo and Sun, Shuo and Kim, Jehyung and Richardson, Christopher and Leavitt, Richard and Solomon, Glenn} } @article { ISI:000436944600001, title = {Search for new physics with atoms and molecules}, journal = {REVIEWS OF MODERN PHYSICS}, volume = {90}, number = {2}, year = {2018}, month = {JUN 29}, pages = {025008}, issn = {0034-6861}, doi = {10.1103/RevModPhys.90.025008}, author = {Safronova, M. S. and Budker, D. and DeMille, D. and Kimball, Derek F. Jackson and Derevianko, A. and Clark, Charles W.} } @article {10056, title = {Second Chern number of a quantum-simulated non-Abelian Yang monopole}, journal = {Science}, volume = {360}, year = {2018}, pages = {1429{\textendash}1434}, abstract = {Topological properties of physical systems are reflected in so-called Chern numbers: A nonzero Chern number typically means that a system is topologically nontrivial. Sugawa et al. engineered a cold atom system with a nonzero second Chern number, in contrast to condensed matter physics, where only the first Chern number is usually invoked. The exotic topology relates to the emergence of a type of magnetic monopole called the Yang monopole (known from theoretical high-energy physics) in a five-dimensional space of internal degrees of freedom in a rubidium Bose-Einstein condensate. The results illustrate the potential of cold atoms physics to simulate high-energy phenomena.Science, this issue p. 1429Topological order is often quantified in terms of Chern numbers, each of which classifies a topological singularity. Here, inspired by concepts from high-energy physics, we use quantum simulation based on the spin degrees of freedom of atomic Bose-Einstein condensates to characterize a singularity present in five-dimensional non-Abelian gauge theories{\textemdash}a Yang monopole. We quantify the monopole in terms of Chern numbers measured on enclosing manifolds: Whereas the well-known first Chern number vanishes, the second Chern number does not. By displacing the manifold, we induce and observe a topological transition, where the topology of the manifold changes to a trivial state.

}, issn = {0036-8075}, doi = {10.1126/science.aam9031}, url = {http://science.sciencemag.org/content/360/6396/1429}, author = {Sugawa, Seiji and Salces-Carcoba, Francisco and Perry, Abigail R. and Yue, Yuchen and Ian B Spielman} } @article { ISI:000430383200001, title = {Single-Particle Mobility Edge in a One-Dimensional Quasiperiodic Optical Lattice}, journal = {PHYSICAL REVIEW LETTERS}, volume = {120}, number = {16}, year = {2018}, month = {APR 19}, pages = {160404}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.120.160404}, author = {Luschen, Henrik P. and Scherg, Sebastian and Kohlert, Thomas and Schreiber, Michael and Bordia, Pranjal and Li, Xiao and S. Das Sarma and Bloch, Immanuel} } @article {10071, title = {A single-photon switch and transistor enabled by a solid-state quantum memory}, journal = {Science}, volume = {361}, year = {2018}, pages = {57}, url = {http://science.sciencemag.org/content/361/6397/57}, author = {Sun, Shuo and Kim, Hyochul and Zhouchen Luo and Glenn S Solomon and Edo Waks} } @article { ISI:000427598600006, title = {Spectral asymmetry of atoms in the van der Waals potential of an optical nanofiber}, journal = {PHYSICAL REVIEW A}, volume = {97}, number = {3}, year = {2018}, month = {MAR 15}, pages = {032509}, issn = {2469-9926}, doi = {10.1103/PhysRevA.97.032509}, author = {Patterson, B. D. and Solano, P. and Julienne, P. S. and Orozco, L. A. and Rolston, S. L.} } @article { ISI:000453476900018, title = {Spin-Mechanical Coupling of an InAs Quantum Dot Embedded in a Mechanical Resonator}, journal = {PHYSICAL REVIEW LETTERS}, volume = {121}, number = {24}, year = {2018}, month = {DEC 14}, pages = {246801}, abstract = {We demonstrate strain-induced coupling between a hole spin in a quantum dot and mechanical motion of a cantilever. The optical transitions of quantum dots integrated into GaAs mechanical resonators are measured synchronously with the motion of the driven resonators. In a Voigt magnetic field, both electron and hole spin splittings are measured, showing negligible change for the electron spin but a large change for the hole spin of up to 36\%. This large effect is attributed to the stronger spin orbit interaction of holes compared to electrons.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.121.246801}, author = {Carter, S. G. and Bracker, A. S. and Bryant, G. W. and Kim, M. and Kim, C. S. and Zalalutdinov, M. K. and Yakes, M. K. and Czarnocki, C. and Casara, J. and Scheibner, M. and Gammon, D.} } @article {9321, title = {Spin-optomechanical coupling between light and a nanofiber torsional mode}, journal = {Opt. Lett.}, volume = {43}, year = {2018}, month = {Apr}, pages = {1534{\textendash}1537}, abstract = {Light that carries linear or angular momentum can interact with a mechanical object, giving rise to optomechanical effects. In particular, a photon can transfer its intrinsic angular momentum to an object when the object either absorbs the photon or changes the photon polarization, as in an action/reaction force pair. Here, we demonstrate resonant driving of torsional mechanical modes of a single-mode tapered optical nanofiber using spin angular momentum. The nanofiber torsional mode spectrum is characterized by polarimetry, showing narrow natural resonances (Q\&\#x2248;2,000). By sending amplitude-modulated light through the nanofiber, we resonantly drive individual torsional modes as a function of the light polarization. By varying the input polarization to the fiber, we find the largest amplification of a mechanical oscillation (\>35\&\#x2009;\&\#x2009;dB) is observed when driving the system with light containing longitudinal spin on the nanofiber waist. These results present optical nanofibers as a platform suitable for quantum spin-optomechanics experiments.

}, keywords = {Fiber optics, Heterodyne, Nanophotonics and photonic crystals, Optomechanics}, doi = {10.1364/OL.43.001534}, url = {http://ol.osa.org/abstract.cfm?URI=ol-43-7-1534}, author = {Eliot F. Fenton and Adnan Khan and Pablo Solano and Luis A. Orozco and Fredrik K. Fatemi} } @article { ISI:000441857400004, title = {Spinor Bose-Einstein-condensate phase-sensitive amplifier for SU(1,1) interferometry}, journal = {PHYSICAL REVIEW A}, volume = {98}, number = {2}, year = {2018}, month = {AUG 16}, pages = {023620}, issn = {2469-9926}, doi = {10.1103/PhysRevA.98.023620}, author = {Wrubel, J. P. and Schwettmann, A. and Fahey, D. P. and Glassman, Z. and Pechkis, H. K. and Griffin, P. F. and Barnett, R. and Tiesinga, E. and Lett, P. D.} } @article { ISI:000448599200008, title = {Structure of correlated worldline theories of quantum gravity}, journal = {PHYSICAL REVIEW D}, volume = {98}, number = {8}, year = {2018}, month = {OCT 29}, pages = {084052}, issn = {2470-0010}, doi = {10.1103/PhysRevD.98.084052}, author = {Barvinsky, A. O. and Carney, D. and Stamp, P. C. E.} } @article {ISI:000423107800020, title = {Synthetic clock transitions via continuous dynamical decoupling}, journal = {PHYSICAL REVIEW A}, volume = {97}, number = {1}, year = {2018}, month = {JAN 16}, pages = {013407}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Decoherence of quantum systems due to uncontrolled fluctuations of the environment presents fundamental obstacles in quantum science. Clock transitions which are insensitive to such fluctuations are used to improve coherence, however, they are not present in all systems or for arbitrary system parameters. Here we create a trio of synthetic clock transitions using continuous dynamical decoupling in a spin-1 Bose-Einstein condensate in which we observe a reduction of sensitivity to magnetic-field noise of up to four orders of magnitude; this work complements the parallelwork byAnderson et al. {[}R. P. Anderson et al., following paper, Phys. Rev. A 97, 013408 (2018)]. In addition, using a concatenated scheme, we demonstrate suppression of sensitivity to fluctuations in our control fields. These field-insensitive states represent an ideal foundation for the next generation of cold-atom experiments focused on fragile many-body phases relevant to quantum magnetism, artificial gauge fields, and topological matter.}, \%\%Address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA}, issn = {2469-9926}, doi = {10.1103/PhysRevA.97.013407}, author = {Trypogeorgos, D. and Valdes-Curiel, A. and Lundblad, N. and Ian B Spielman} } @article { ISI:000428165400006, title = {Thermal management and non-reciprocal control of phonon flow via optomechanics}, journal = {NATURE COMMUNICATIONS}, volume = {9}, year = {2018}, month = {MAR 23}, pages = {1207}, issn = {2041-1723}, doi = {10.1038/s41467-018-03624-y}, author = {Seif, Alireza and DeGottardi, Wade and Esfarjani, Keivan and Hafezi, Mohammad} } @article { ISI:000438196300002, title = {Topological band crossings in hexagonal materials}, journal = {PHYSICAL REVIEW MATERIALS}, volume = {2}, number = {7}, year = {2018}, month = {JUL 11}, pages = {074201}, issn = {2475-9953}, doi = {10.1103/PhysRevMaterials.2.074201}, author = {Zhang, J. and Chan, Y-H. and Chiu, C-K. and Vergniory, M. G. and Schoop, L. M. and Schnyder, A. P.} } @article {ISI:000431525200001, title = {Topological lattice using multi-frequency radiation}, journal = {NEW JOURNAL OF PHYSICS}, volume = {20}, year = {2018}, month = {MAY 3}, pages = {055001}, publisher = {IOP PUBLISHING LTD}, type = {Article}, abstract = {We describe a novel technique for creating an artificial magnetic field for ultracold atoms using a periodically pulsed pair of counter propagating Raman lasers that drive transitions between a pair of internal atomic spin states: a multi-frequency coupling term. In conjunction with a magnetic field gradient, this dynamically generates a rectangular lattice with a non-staggered magnetic flux. For a wide range of parameters, the resulting Bloch bands have non-trivial topology, reminiscent of Landau levels, as quantified by their Chern numbers.}, \%\%Address = {TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND}, keywords = {artificial gauge fields, Floquet, flux lattice}, issn = {1367-2630}, doi = {10.1088/1367-2630/aab7a3}, author = {Andrijauskas, Tomas and Ian B Spielman and Juzeliunas, Gediminas} } @article { ISI:000432974400003, title = {Two Clock Transitions in Neutral Yb for the Highest Sensitivity to Variations of the Fine-Structure Constant}, journal = {PHYSICAL REVIEW LETTERS}, volume = {120}, number = {17}, year = {2018}, month = {APR 27}, pages = {173001}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.120.173001}, author = {Safronova, Marianna S. and Porsev, Sergey G. and Sanner, Christan and Ye, Jun} } @article { ISI:000428507500006, title = {Ultracold Anions for High-Precision Antihydrogen Experiments}, journal = {PHYSICAL REVIEW LETTERS}, volume = {120}, number = {13}, year = {2018}, month = {MAR 28}, pages = {133205}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.120.133205}, author = {Cerchiari, G. and Kellerbauer, A. and Safronova, M. S. and Safronova, U. I. and Yzombard, P.} } @article { ISI:000419468200001, title = {Universal many-body response of heavy impurities coupled to a Fermi sea: a review of recent progress}, journal = {REPORTS ON PROGRESS IN PHYSICS}, volume = {81}, number = {2}, year = {2018}, month = {FEB}, pages = {024401}, keywords = {Fermi gas, Feshbach resonances, functional determinants, non-equilibrium dynamics, orthogonality catastrophe, quantum impurities}, issn = {0034-4885}, doi = {10.1088/1361-6633/aa9593}, author = {Schmidt, Richard and Knap, Michael and Ivanov, Dmitri A. and You, Jhih-Shih and Cetina, Marko and Demler, Eugene} } @article {10436, title = {Unscrambling the physics of out-of-time-order correlators}, journal = {Nature Physics}, volume = {14}, year = {2018}, pages = {988{\textendash}990}, abstract = {Quantitative tools for measuring the propagation of information through quantum many-body systems, originally developed to study quantum chaos, have recently found many new applications from black holes to disordered spin systems.

}, isbn = {1745-2481}, doi = {10.1038/s41567-018-0295-5}, url = {https://doi.org/10.1038/s41567-018-0295-5}, author = {Swingle, Brian} } @article { ISI:000449675500001, title = {Unsupervised phase mapping of X-ray diffraction data by nonnegative matrix factorization integrated with custom clustering}, journal = {NPJ COMPUTATIONAL MATERIALS}, volume = {4}, year = {2018}, month = {AUG 6}, pages = {UNSP 43}, issn = {2057-3960}, doi = {10.1038/s41524-018-0099-2}, author = {Stanev, Valentin and Vesselinov, Velimir V. and Kusne, A. Gilad and Antoszewski, Graham and Takeuchi, Ichiro and Alexandrov, Boian S.} } @article {10331, title = {Weak-link Josephson Junctions Made from Topological Crystalline Insulators}, journal = {Phys. Rev. Lett.}, volume = {121}, year = {2018}, month = {Aug}, pages = {097701}, doi = {10.1103/PhysRevLett.121.097701}, url = {https://link.aps.org/doi/10.1103/PhysRevLett.121.097701}, author = {Snyder, R. A. and Trimble, C. J. and Rong, C. C. and Folkes, P. A. and Taylor, P. J. and James R. Williams} } @article {ISI:000391848000004, title = {8 pi-periodic dissipationless ac Josephson effect on a quantum spin Hall edge via a quantum magnetic impurity}, journal = {PHYSICAL REVIEW B}, volume = {95}, number = {1}, year = {2017}, month = {JAN 9}, pages = {014505}, abstract = {Time-reversal invariance places strong constraints on the properties of the quantum spin Hall edge. One such restriction is the inevitability of dissipation in a Josephson junction between two superconductors formed on such an edge without the presence of interaction. Interactions and spin-conservation breaking are key ingredients for the realization of the dissipationless ac Josephson effect on such quantum spin Hall edges. We present a simple quantum impurity model that allows us to create a dissipationless fractional Josephson effect on a quantum spin Hall edge. We then use this model to substantiate a general argument that shows that any such nondissipative Josephson effect must necessarily be 8 pi periodic.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.95.014505}, author = {Hui, Hoi-Yin and Sau, Jay D.} } @article { ISI:000408620800002, title = {Andreev bound states versus Majorana bound states in quantum dot-nanowire-superconductor hybrid structures: Trivial versus topological zero-bias conductance peaks}, journal = {PHYSICAL REVIEW B}, volume = {96}, number = {7}, year = {2017}, month = {AUG 30}, issn = {2469-9950}, doi = {10.1103/PhysRevB.96.075161}, author = {Liu, Chun-Xiao and Sau, Jay D. and Stanescu, Tudor D. and S. Das Sarma} } @article {ISI:000395511400052, title = {Brownian motion of solitons in a Bose-Einstein condensate}, journal = {PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, volume = {114}, number = {10}, year = {2017}, month = {MAR 7}, pages = {2503-2508}, abstract = {We observed and controlled the Brownian motion of solitons. We launched solitonic excitations in highly elongated Rb-87 Bose-Einstein condensates (BECs) and showed that a dilute background of impurity atoms in a different internal state dramatically affects the soliton. With no impurities and in one dimension (1D), these solitons would have an infinite lifetime, a consequence of integrability. In our experiment, the added impurities scatter off the much larger soliton, contributing to its Brownian motion and decreasing its lifetime. We describe the soliton{\textquoteright}s diffusive behavior using a quasi-1D scattering theory of impurity atoms interacting with a soliton, giving diffusion coefficients consistent with experiment.

}, issn = {0027-8424}, doi = {10.1073/pnas.1615004114}, author = {Aycock, Lauren M. and Hurst, Hilary M. and Efimkin, Dmitry K. and Genkina, Dina and Lu, Hsin-I and Galitski, Victor M. and Ian B Spielman} } @article { ISI:000405364100004, title = {Chiral anomaly and longitudinal magnetotransport in type-II Weyl semimetals}, journal = {PHYSICAL REVIEW B}, volume = {96}, number = {4}, year = {2017}, month = {JUL 13}, issn = {2469-9950}, doi = {10.1103/PhysRevB.96.045112}, author = {Sharma, Girish and Goswami, Pallab and Tewari, Sumanta} } @article { ISI:000406910800004, title = {Conductance of a superconducting Coulomb-blockaded Majorana nanowire}, journal = {PHYSICAL REVIEW B}, volume = {96}, number = {5}, year = {2017}, month = {AUG 4}, issn = {2469-9950}, doi = {10.1103/PhysRevB.96.054504}, author = {Chiu, Ching-Kai and Sau, Jay D. and S. Das Sarma} } @article {ISI:000391308200002, title = {Conductance spectroscopy of nontopological-topological superconductor junctions}, journal = {PHYSICAL REVIEW B}, volume = {95}, number = {2}, year = {2017}, month = {JAN 6}, pages = {020501}, abstract = {We calculate the zero-temperature differential conductance dI/dV of a voltage-biased one-dimensional junction between a nontopological and a topological superconductor for arbitrary junction transparency using the scattering matrix formalism. We consider two representative models for the topological superconductors: (i) spinful p-wave and (ii) s-wave with spin-orbit coupling and spin splitting. We verify that in the tunneling limit (small junction transparencies) where only single Andreev reflections contribute to the current, the conductance for voltages below the nontopological superconductor gap Delta(s) is zero and there are two symmetric conductance peaks appearing at eV = +/-Delta(s). with the quantized value (4-pi)2e(2)/h due to resonant Andreev reflection from the Majorana zero mode. However, when the junction transparency is not small, there is a finite conductance for e vertical bar V vertical bar \< Delta(s) arising from multiple Andreev reflections. The conductance at eV = +/-Delta(s). in this case is no longer quantized. In general, the conductance is particle-hole asymmetric except for sufficiently small transparencies. We further show that, for certain values of parameters, the tunneling conductance from a zero-energy conventional Andreev bound state can be made to mimic the conductance from a true Majorana mode.

}, issn = {2469-9950}, doi = {10.1102/PhysRevB.95.020501}, author = {Setiawan, F. and Cole, William S. and Sau, Jay D. and S. Das Sarma} } @article {ISI:000396095500001, title = {Detecting topological superconductivity using low-frequency doubled Shapiro steps}, journal = {PHYSICAL REVIEW B}, volume = {95}, number = {6}, year = {2017}, month = {FEB 3}, pages = {060501}, abstract = {The fractional Josephson effect has been observed in many instances as a signature of a topological superconducting state containing zero-energy Majorana modes. We present a nontopological scenario which can produce a fractional Josephson effect generically in semiconductor-based Josephson junctions, namely, a resonant impurity bound state weakly coupled to a highly transparent channel. We show that the fractional ac Josephson effect can be generated by the Landau-Zener processes which flip the electron occupancy of the impurity bound state. The Josephson effect signature for Majorana modes become distinct from this nontopological scenario only at low frequency. We prove that a variant of the fractional ac Josephson effect, namely, the low-frequency doubled Shapiro steps, can provide a more reliable signature of the topological superconducting state.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.95.060501}, author = {Sau, Jay D. and Setiawan, F.} } @article { ISI:000414365000002, title = {Development of a new UHV/XHV pressure standard (cold atom vacuum standard)}, journal = {METROLOGIA}, volume = {54}, number = {6}, year = {2017}, month = {DEC}, pages = {S125-S132}, issn = {0026-1394}, doi = {10.1088/1681-7575/aa8a7b}, author = {Scherschligt, Julia and Fedchak, James A. and Barker, Daniel S. and Eckel, Stephen and Klimov, Nikolai and Makrides, Constantinos and Tiesinga, Eite} } @article { ISI:000407923500006, title = {Dispersive optical detection of magnetic Feshbach resonances in ultracold gases}, journal = {PHYSICAL REVIEW A}, volume = {96}, number = {2}, year = {2017}, month = {AUG 18}, issn = {2469-9926}, doi = {10.1103/PhysRevA.96.022705}, author = {Sawyer, Bianca J. and Horvath, Milena S. J. and Tiesinga, Eite and Deb, Amita B. and Kjaergaard, Niels} } @article {ISI:000404466500004, title = {Dynamic zero modes of Dirac fermions and competing singlet phases of antiferromagnetic order}, journal = {PHYSICAL REVIEW B}, volume = {95}, number = {22}, year = {2017}, month = {JUN 30}, pages = {224438}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {In quantum spin systems, singlet phases often develop in the vicinity of an antiferromagnetic order. Typical settings for such problems arise when itinerant fermions are also present. In this paper, we develop a theoretical framework for \%\%Addressing such competing orders in an itinerant system, described by Dirac fermions strongly coupled to an O(3) nonlinear sigma model. We focus on two spatial dimensions, where upon disordering the antiferromagnetic order by quantum fluctuations the singular tunneling events also known as (anti) hedgehogs can nucleate competing singlet orders in the paramagnetic phase. In the presence of an isolated hedgehog configuration of the nonlinear sigma model field, we show that the fermion determinant vanishes as the dynamic Euclidean Dirac operator supports fermion zero modes of definite chirality. This provides a topological mechanism for suppressing the tunneling events. Using the methodology of quantum chromodynamics, we evaluate the fermion determinant in the close proximity of magnetic quantum phase transition, when the antiferromagnetic order-parameter field can be described by a dilute gas of hedgehogs and antihedgehogs. We show how the precise nature of emergent singlet order is determined by the overlap between dynamic fermion zero modes of opposite chirality, localized on the hedgehogs and antihedgehogs. For a Kondo-Heisenberg model on the honeycomb lattice, we demonstrate the competition between spin Peierls order and Kondo singlet formation, thereby elucidating its global phase diagram. We also discuss other physical problems that can be \%\%Addressed within this general framework.}, \%\%Address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA}, issn = {2469-9950}, doi = {10.1103/PhysRevB.95.224438}, author = {Goswami, Pallab and Si, Qimiao} } @article {7616, title = {Dynamics of trapped atoms around an optical nanofiber probed through polarimetry}, journal = {Opt. Lett.}, volume = {42}, year = {2017}, month = {Jun}, pages = {2283{\textendash}2286}, abstract = {The evanescent field outside an optical nanofiber (ONF) can create optical traps for neutral atoms. We present a non-destructive method to characterize such trapping potentials. An off-resonance linearly polarized probe beam that propagates through the ONF experiences a slow axis of polarization produced by trapped atoms on opposite sides along the ONF. The transverse atomic motion is imprinted onto the probe polarization through the changing atomic index of refraction. By applying a transient impulse, we measure a time-dependent polarization rotation of the probe beam that provides both a rapid and non-destructive measurement of the optical trapping frequencies.

}, keywords = {Fiber optics, Heterodyne, Laser trapping, Nanophotonics and photonic crystals}, doi = {10.1364/OL.42.002283}, url = {http://ol.osa.org/abstract.cfm?URI=ol-42-12-2283}, author = {Pablo Solano and Fredrik K. Fatemi and Luis A. Orozco and S. L. Rolston} } @article {ISI:000400662700004, title = {Effects of spin-orbit coupling on zero-energy bound states localized at magnetic impurities in multiband superconductors}, journal = {PHYSICAL REVIEW B}, volume = {95}, number = {20}, year = {2017}, month = {MAY 5}, abstract = {We investigate the effect of spin-orbit coupling on the in-gap bound states localized at magnetic impurities in multiband superconductors with unconventional (sign-changed) and conventional (sign-unchanged) s-wave pairing symmetry, which may be relevant to iron-based superconductors. Without spin-orbit coupling, for spin-singlet superconductors it is known that such bound states cross zero energy at a critical value of the impurity scattering strength and acquire a finite spin polarization. Moreover, the degenerate, spin-polarized, zero-energy bound states are unstable to applied Zeeman fields as well as a deviation of the impurity scattering strength away from criticality. Using a T-matrix formalism as well as analytical arguments, we show that, in the presence of spin-orbit coupling, the zero-energy bound states localized at magnetic impurities in unconventional, sign-changed, s-wave superconductors acquire surprising robustness to applied Zeeman fields and variation in the impurity scattering strength, an effect which is absent in the conventional, sign-unchanged, s-wave superconductors. Given that the iron-based multiband superconductors may possess a substantial spin-orbit coupling as seen in recent experiments, our results may provide one possible explanation to the recent observation of surprisingly robust zero bias scanning tunneling microscope peaks localized at magnetic impurities in iron-based superconductors provided the order parameter symmetry is sign changing s(+-)-wave.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.95.205107}, author = {Seo, Kangjun and Sau, Jay D. and Tewari, Sumanta} } @article { ISI:000416023400007, title = {Electron temperature and tunnel coupling dependence of zero-bias and almost-zero-bias conductance peaks in Majorana nanowires}, journal = {PHYSICAL REVIEW B}, volume = {96}, number = {18}, year = {2017}, month = {NOV 22}, issn = {2469-9950}, doi = {10.1103/PhysRevB.96.184520}, author = {Setiawan, F. and Liu, Chun-Xiao and Sau, Jay D. and S. Das Sarma} } @article { ISI:000412747900001, title = {Electron transport in nodal-line semimetals}, journal = {PHYSICAL REVIEW B}, volume = {96}, number = {16}, year = {2017}, month = {OCT 11}, issn = {2469-9950}, doi = {10.1103/PhysRevB.96.161105}, author = {Syzranov, S. V. and Skinner, B.} } @conference {ISI:000423026400014, title = {Entangled Photons in 2D Topological Photonic Systems}, booktitle = {ACTIVE PHOTONIC PLATFORMS IX}, series = {Proceedings of SPIE}, volume = {10345}, year = {2017}, note = {Conference on Active Photonic Platforms IX, San Diego, CA, AUG 06-10, 2017}, pages = {UNSP 103451U}, publisher = {SPIE}, organization = {SPIE}, type = {Proceedings Paper}, abstract = {We study transport of time-bin entangled photon pairs in a 2D topological photonic system of coupled ring resonators. We show that the transport through edge bands preserves temporal correlations of input photons. Furthermore, edge transport is robust against system disorder and only marginally affects the temporal correlations of photons. In contrast, transport through bulk band leads to unwanted bunching/anti-bunching of photons and the probability of bunching/anti-bunching increases with increasing disorder. Finally, we discuss our experimentally efforts to demonstrate the robustness of edge states for quantum transport.}, \%\%Address = {1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA}, keywords = {edge states, quantum transport, Topological photonics}, isbn = {978-1-5106-1148-1; 978-1-5106-1147-4}, issn = {0277-786X}, doi = {10.1117/12.2275292}, author = {Mittal, Sunil and Orrc, Venkata Vikram and Hafezi, Mohammad}, editor = {Subramania, GS and Foteinopoulou, S} } @article { ISI:000413668800012, title = {Evidence for magnetic Weyl fermions in a correlated metal}, journal = {NATURE MATERIALS}, volume = {16}, number = {11}, year = {2017}, month = {NOV}, pages = {1090+}, issn = {1476-1122}, doi = {10.1038/NMAT4987}, author = {Kuroda, K. and Tomita, T. and Suzuki, M. -T. and Bareille, C. and Nugroho, A. A. and Goswami, P. and Ochi, M. and Ikhlas, M. and Nakayama, M. and Akebi, S. and Noguchi, R. and Ishii, R. and Inami, N. and Ono, K. and Kumigashira, H. and Varykhalov, A. and Muro, T. and Koretsune, T. and Arita, R. and Shin, S. and Kondo, Takeshi and Nakatsuji, S.} } @article { ISI:000411592600023, title = {Experimental phase diagram of zero-bias conductance peaks in superconductor/semiconductor nanowire devices}, journal = {SCIENCE ADVANCES}, volume = {3}, number = {9}, year = {2017}, month = {SEP}, issn = {2375-2548}, doi = {10.1126/sciadv.1701476}, author = {Chen, Jun and Yu, Peng and Stenger, John and Hocevar, Moira and Car, Diana and Plissard, Sebastien R. and Bakkers, Erik P. A. M. and Stanescu, Tudor D. and Frolov, Sergey M.} } @article { ISI:000412979000001, title = {Experimental Study of Optimal Measurements for Quantum State Tomography}, journal = {PHYSICAL REVIEW LETTERS}, volume = {119}, number = {15}, year = {2017}, month = {OCT 13}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.119.150401}, author = {Sosa-Martinez, H. and Lysne, N. K. and Baldwin, C. H. and Kalev, A. and Deutsch, I. H. and Jessen, P. S.} } @article {ISI:000402483300015, title = {Global Phase Diagram of a Three-Dimensional Dirty Topological Superconductor}, journal = {PHYSICAL REVIEW LETTERS}, volume = {118}, number = {22}, year = {2017}, month = {JUN 1}, pages = {227002}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We investigate the phase diagram of a three-dimensional, time-reversal symmetric topological superconductor in the presence of charge impurities and random s-wave pairing. Combining complimentary field theoretic and numerical methods, we show that the quantum phase transition between two topologically distinct paired states (or thermal insulators), described by thermal Dirac semimetal, remains unaffected in the presence of sufficiently weak generic randomness. At stronger disorder, however, these two phases are separated by an intervening thermal metallic phase of diffusive Majorana fermions. We show that across the insulator-insulator and metal-insulator transitions, normalized thermal conductance displays single parameter scaling, allowing us to numerically extract the critical exponents across them. The pertinence of our study in strong spin-orbit coupled, three-dimensional doped narrow gap semiconductors, such as CuxBi2Se3, is discussed.}, \%\%Address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.118.227002}, author = {Roy, Bitan and Alavirad, Yahya and Sau, Jay D.} } @article { ISI:000414531800009, title = {High-performance semiconductor quantum-dot single-photon sources}, journal = {NATURE NANOTECHNOLOGY}, volume = {12}, number = {11}, year = {2017}, month = {NOV}, pages = {1026-1039}, issn = {1748-3387}, doi = {10.1038/NNANO.2017.218}, author = {Senellart, Pascale and Solomon, Glenn and White, Andrew} } @article { ISI:000411529000031, title = {Improved measurement of two-mode quantum correlations using a phase-sensitive amplifier}, journal = {OPTICS EXPRESS}, volume = {25}, number = {18}, year = {2017}, month = {SEP 4}, pages = {21301-21311}, issn = {1094-4087}, doi = {10.1364/OE.25.021301}, author = {Li, Tian and Anderson, Brian E. and Horrom, Travis and Schmittberger, Bonnie L. and Jones, Kevin M. and Lett, Paul D.} } @article {ISI:000419193700019, title = {Interfacing a quantum dot with a spontaneous parametric down-conversion source}, journal = {QUANTUM SCIENCE AND TECHNOLOGY}, volume = {2}, number = {3}, year = {2017}, month = {SEP 1}, pages = {UNSP 034016}, publisher = {IOP PUBLISHING LTD}, type = {Article}, abstract = {Quantum networks require interfacing stationary and flying qubits. These flying qubits are usually nonclassical states of light. Here we consider two of the leading source technologies for nonclassical light, spontaneous parametric down-conversion and single semiconductor quantum dots. Down-conversion delivers high-grade entangled photon pairs, whereas quantum dots excel at producing single photons. We report on an experiment that joins these two technologies and investigates the conditions under which optimal interference between these dissimilar light sources may be achieved.}, \%\%Address = {TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND}, keywords = {heralded single photons, Hong-Ou-Mandel interference, Quantum Dots, quantum interfaces}, issn = {2058-9565}, doi = {10.1088/2058-9565/aa7b65}, author = {Huber, Tobias and Prilmueller, Maximilian and Sehner, Michael and Solomon, Glenn S. and Predojevic, Ana and Weihs, Gregor} } @article { ISI:000408565900007, title = {Ionization enhancement and suppression by phase-locked ultrafast pulse pairs}, journal = {PHYSICAL REVIEW A}, volume = {96}, number = {2}, year = {2017}, month = {AUG 29}, issn = {2469-9926}, doi = {10.1103/PhysRevA.96.023425}, author = {Foote, David B. and Lin, Y. and Pi, Liang-Wen and Djiokap, J. M. Ngoko and Starace, Anthony F. and Hill, III, W. T.} } @article { ISI:000413372300001, title = {Ising quantum criticality in Majorana nanowires}, journal = {PHYSICAL REVIEW B}, volume = {96}, number = {13}, year = {2017}, month = {OCT 20}, issn = {2469-9950}, doi = {10.1103/PhysRevB.96.134517}, author = {Cole, William S. and Sau, Jay D. and S. Das Sarma} } @article {ISI:000400652700006, title = {Kinetic theory of dark solitons with tunable friction}, journal = {PHYSICAL REVIEW A}, volume = {95}, number = {5}, year = {2017}, month = {MAY 3}, abstract = {We study controllable friction in a system consisting of a dark soliton in a one-dimensional Bose-Einstein condensate coupled to a noninteracting Fermi gas. The fermions act as impurity atoms, not part of the original condensate, that scatter off of the soliton. We study semiclassical dynamics of the dark soliton, a particlelike object with negative mass, and calculate its friction coefficient. Surprisingly, it depends periodically on the ratio of interspecies (impurity-condensate) to intraspecies (condensate-condensate) interaction strengths. By tuning this ratio, one can access a regime where the friction coefficient vanishes. We develop a general theory of stochastic dynamics for negative-mass objects and find that their dynamics are drastically different from their positive-mass counterparts: they do not undergo Brownian motion. From the exact phase-space probability distribution function (i.e., in position and velocity), we find that both the trajectory and lifetime of the soliton are altered by friction, and the soliton can undergo Brownian motion only in the presence of friction and a confining potential. These results agree qualitatively with experimental observations by Aycock et al. {[}Proc. Natl. Acad. Sci. USA 114, 2503 (2017)] in a similar system with bosonic impurity scatterers.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.95.053604}, author = {Hurst, Hilary M. and Efimkin, Dmitry K. and Ian B Spielman and Galitski, Victor} } @article { ISI:000406382800003, title = {Methods, analysis, and the treatment of systematic errors for the electron electric dipole moment search in thorium monoxide}, journal = {NEW JOURNAL OF PHYSICS}, volume = {19}, year = {2017}, month = {JUL 25}, issn = {1367-2630}, doi = {10.1088/1367-2630/aa708e}, author = {Baron, J. and Campbell, W. C. and DeMille, D. and Doyle, J. M. and Gabrielse, G. and Gurevich, Y. V. and Hess, P. W. and Hutzler, N. R. and Kirilov, E. and Kozyryev, I. and O{\textquoteright}Leary, B. R. and Panda, C. D. and Parsons, M. F. and Spaun, B. and Vutha, A. C. and West, A. D. and West, E. P. and ACME Collaboration} } @article {6496, title = {Modal interference in optical nanofibers for sub-Angstrom radius sensitivity}, journal = {Optica}, volume = {4}, year = {2017}, month = {Jan}, pages = {157{\textendash}162}, abstract = {Optical nanofibers (ONFs) of sub-wavelength dimensions confine light in modes with a strong evanescent field that can trap, probe, and manipulate nearby quantum systems. To measure the evanescent field and propagating modes and to optimize ONF performance, a surface probe is desirable during fabrication. We demonstrate a nondestructive near-field measurement of light propagation in ONFs by sampling the local evanescent field with a microfiber. This approach reveals the behavior of all propagating modes, and because the modal beat lengths in cylindrical waveguides depend strongly on the radius, it simultaneously provides exquisite sensitivity to the ONF radius. We show that our measured spatial frequencies provide a map of the average ONF radius (over a 600\&\#x00A0;\&\#x03BC;m window) along the 10\&\#x00A0;mm ONF waist with a 40\&\#x00A0;pm resolution and a high signal-to-noise ratio. The measurements agree with scanning electron microscopy (SEM) to within SEM instrument resolutions. This fast method is immune to polarization, intrinsic birefringence, mechanical vibrations, and scattered light and provides a set of constraints to protect from systematic errors in the measurements.

}, keywords = {Fiber characterization, Fiber optics, Nanophotonics and photonic crystals}, doi = {https://doi.org/10.1364/OPTICA.4.000157}, url = {http://www.osapublishing.org/optica/abstract.cfm?URI=optica-4-1-157}, author = {Fredrik K. Fatemi and Jonathan E. Hoffman and Pablo Solano and Eliot F. Fenton and Guy Beadie and Steven L. Rolston and Luis A. Orozco} } @article {7296, title = {Multispecies Trapped-Ion Node for Quantum Networking}, journal = {Phys. Rev. Lett.}, volume = {118}, year = {2017}, month = {Jun}, pages = {250502}, doi = {10.1103/PhysRevLett.118.250502}, url = {https://link.aps.org/doi/10.1103/PhysRevLett.118.250502}, author = {Inlek, I. V. and Crocker, C. and Lichtman, M. and Sosnova, K. and Monroe, C.} } @article { ISI:000413927000009, title = {Non-thermalization in trapped atomic ion spin chains}, journal = {PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES}, volume = {375}, number = {2108}, year = {2017}, month = {DEC 13}, issn = {1364-503X}, doi = {10.1098/rsta.2017.0107}, author = {Hess, P. W. and Becker, P. and Kaplan, H. B. and Kyprianidis, A. and Lee, A. C. and Neyenhuis, B. and Pagano, G. and Richerme, P. and Senko, C. and Smith, J. and Tan, W. L. and Zhang, J. and Monroe, C.} } @article {6701, title = {Observation of a discrete time crystal}, journal = {Nature}, volume = {543}, year = {2017}, month = {03/2017}, pages = {217-220}, chapter = {217}, keywords = {ions, many-body localization, time crystal}, doi = {10.1038/nature21413}, author = {J Zhang and P W. Hess and A Kyprianidis and P Becker and A Lee and J Smith and G Pagano and I.-D Potirniche and A C. Potter and A Vishwanath and N Y. Yao and C Monroe} } @article {7481, title = {Observation of prethermalization in long-range interacting spin chains}, journal = {Science Advances}, volume = {3}, year = {2017}, abstract = {Although statistical mechanics describes thermal equilibrium states, these states may or may not emerge dynamically for a subsystem of an isolated quantum many-body system. For instance, quantum systems that are near-integrable usually fail to thermalize in an experimentally realistic time scale, and instead relax to quasi-stationary prethermal states that can be described by statistical mechanics, when approximately conserved quantities are included in a generalized Gibbs ensemble (GGE). We experimentally study the relaxation dynamics of a chain of up to 22 spins evolving under a long-range transverse-field Ising Hamiltonian following a sudden quench. For sufficiently long-range interactions, the system relaxes to a new type of prethermal state that retains a strong memory of the initial conditions. However, the prethermal state in this case cannot be described by a standard GGE; it rather arises from an emergent double-well potential felt by the spin excitations. This result shows that prethermalization occurs in a broader context than previously thought, and reveals new challenges for a generic understanding of the thermalization of quantum systems, particularly in the presence of long-range interactions.

}, doi = {10.1126/sciadv.1700672}, url = {http://advances.sciencemag.org/content/3/8/e1700672}, author = {Neyenhuis, Brian and Zhang, Jiehang and Hess, Paul W. and Smith, Jacob and Lee, Aaron C. and Richerme, Phil and Gong, Zhe-Xuan and Gorshkov, Alexey V. and Monroe, Christopher} } @inbook {7621, title = {Optical Nanofibers: A New Platform for Quantum Optics}, booktitle = {Advances In Atomic, Molecular, and Optical Physics}, volume = {66}, year = {2017}, pages = {439}, chapter = {7}, author = {Pablo Solano and Grover, J. A. and Jonathan E Hoffman and Sylvain Ravets and Fredrik K Fatemi and Luis A Orozco and Steven L Rolston} } @article {ISI:000404461300009, title = {Optimal phase measurements with bright- and vacuum-seeded SU(1,1) interferometers}, journal = {PHYSICAL REVIEW A}, volume = {95}, number = {6}, year = {2017}, month = {JUN 27}, pages = {063843}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {The SU(1,1) interferometer can be thought of as a Mach-Zehnder interferometer with its linear beam splitters replaced with parametric nonlinear optical processes. We consider the cases of bright- and vacuum-seeded SU(1,1) interferometers using intensity or homodyne detectors. A simplified truncated scheme with only one nonlinear interaction is introduced, which not only beats conventional intensity detection with a bright seed, but can saturate the phase-sensitivity bound set by the quantum Fisher information. We also show that the truncated scheme achieves a sub-shot-noise phase sensitivity in the vacuum-seeded case, despite the phase-sensing optical beams having no well-defined phase.}, \%\%Address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA}, issn = {2469-9926}, doi = {10.1103/PhysRevA.95.063843}, author = {Anderson, Brian E. and Schmittberger, Bonnie L. and Gupta, Prasoon and Jones, Kevin M. and Lett, Paul D.} } @article { ISI:000411527100054, title = {Optomechanical Analogy for Toy Cosmology with Quantized Scale Factor}, journal = {ENTROPY}, volume = {19}, number = {9}, year = {2017}, month = {SEP}, issn = {1099-4300}, doi = {10.3390/e19090485}, author = {Smiga, Joseph A. and Taylor, Jacob M.} } @article { ISI:000406093300012, title = {Phase sensing beyond the standard quantum limit with a variation on the SU(1,1) interferometer}, journal = {OPTICA}, volume = {4}, number = {7}, year = {2017}, month = {JUL 20}, pages = {752-756}, issn = {2334-2536}, doi = {10.1364/OPTICA.4.000752}, author = {Anderson, Brian E. and Gupta, Prasoon and Schmittberger, Bonnie L. and Horrom, Travis and Hermann-Avigliano, Carla and Jones, Kevin M. and Lett, Paul D.} } @article { ISI:000408619600008, title = {Phenomenology of the soft gap, zero-bias peak, and zero-mode splitting in ideal Majorana nanowires}, journal = {PHYSICAL REVIEW B}, volume = {96}, number = {5}, year = {2017}, month = {AUG 30}, issn = {2469-9950}, doi = {10.1103/PhysRevB.96.054520}, author = {Liu, Chun-Xiao and Setiawan, F. and Sau, Jay D. and S. Das Sarma} } @article { ISI:000405697200005, title = {Proximity-induced low-energy renormalization in hybrid semiconductor-superconductor Majorana structures}, journal = {PHYSICAL REVIEW B}, volume = {96}, number = {1}, year = {2017}, month = {JUL 17}, issn = {2469-9950}, doi = {10.1103/PhysRevB.96.014510}, author = {Stanescu, Tudor D. and S. Das Sarma} } @article {7271, title = {Quantum correlations from a room-temperature optomechanical cavity}, journal = {Science}, volume = {356}, year = {2017}, pages = {1265{\textendash}1268}, abstract = {Quantum back action{\textemdash}the {\textquotedblleft}reaction{\textquotedblright} of a quantum mechanical object to being measured{\textemdash}is normally observed at cryogenic temperatures, where it is easier to distinguish from thermal motion. Purdy et al. managed to tease out the effects of quantum back action at room temperature by using a mechanical oscillator and probing it with light (see the Perspective by Harris). The fluctuations of the force produced by the light probe caused correlated changes to the motion of the oscillator and the properties of the transmitted light. These correlations revealed the effects of the back action, which allows the system to be used as a quantum thermometer.Science, this issue p. 1265; see also p. 1232The act of position measurement alters the motion of an object being measured. This quantum measurement backaction is typically much smaller than the thermal motion of a room-temperature object and thus difficult to observe. By shining laser light through a nanomechanical beam, we measure the beam{\textquoteright}s thermally driven vibrations and perturb its motion with optical force fluctuations at a level dictated by the Heisenberg measurement-disturbance uncertainty relation. We demonstrate a cross-correlation technique to distinguish optically driven motion from thermally driven motion, observing this quantum backaction signature up to room temperature. We use the scale of the quantum correlations, which is determined by fundamental constants, to gauge the size of thermal motion, demonstrating a path toward absolute thermometry with quantum mechanically calibrated ticks.

}, issn = {0036-8075}, doi = {10.1126/science.aag1407}, url = {http://science.sciencemag.org/content/356/6344/1265}, author = {Purdy, T. P. and Grutter, K. E. and Srinivasan, K. and Taylor, J. M.} } @article {ISI:000396518400037, title = {Quantum frequency bridge: high-accuracy characterization of a nearly-noiseless parametric frequency converter}, journal = {OPTICS EXPRESS}, volume = {25}, number = {2}, year = {2017}, month = {JAN 23}, pages = {907-917}, abstract = {We demonstrate an efficient and inherently ultra-low noise frequency conversion via a parametric sum frequency generation. Due to the wide separation between the input and pump frequencies and the low pump frequency relative to the input photons, the upconversion results in only approximate to 100 background photons per hour. To measure such a low rate, we introduced a dark count reduction algorithm for an optical transition edge sensor. (C) 2017 Optical Society of America}, issn = {1094-4087}, doi = {10.1364/OE.25.000907}, author = {Burenkov, Ivan A. and Gerrits, Thomas and Lita, Adriana and Nam, Sae Woo and Shalm, L. Krister and Polyakov, Sergey V.} } @article {ISI:000418652100002, title = {Quantum phases of two-component bosons with spin-orbit coupling in optical lattices}, journal = {PHYSICAL REVIEW A}, volume = {96}, number = {6}, year = {2017}, month = {DEC 26}, pages = {061603}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Ultracold bosons in optical lattices are one of the few systems where bosonic matter is known to exhibit strong correlations. Here we push the frontier of our understanding of interacting bosons in optical lattices by adding synthetic spin-orbit coupling, and show that new kinds of density and chiral orders develop. The competition between the optical lattice period and the spin-orbit coupling length-which can be made comparable in experiments-along with the spin hybridization induced by a transverse field (i.e., Rabi coupling) and interparticle interactions create a rich variety of quantum phases including uniform, nonuniform, and phase-separated superfluids, as well as Mott insulators. The spontaneous symmetry-breaking phenomena at the transitions between them are explained by a two-order-parameter Ginzburg-Landau model with multiparticle umklapp processes. Finally, in order to characterize each phase, we calculated their experimentally measurable crystal momentum distributions.}, \%\%Address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA}, issn = {2469-9926}, doi = {10.1103/PhysRevA.96.061603}, author = {Yamamoto, Daisuke and Ian B Spielman and de Melo, C. A. R. Sa} } @article {ISI:000418786600007, title = {Quantum Redirection of Antenna Absorption to Photosynthetic Reaction Centers}, journal = {JOURNAL OF PHYSICAL CHEMISTRY LETTERS}, volume = {8}, number = {24}, year = {2017}, month = {DEC 21}, pages = {6015-6021}, publisher = {AMER CHEMICAL SOC}, type = {Article}, abstract = {The early steps of photosynthesis involve the photoexcitation of reaction centers (RCs) and light-harvesting (LH) units. Here, we show that the historically overlooked excitonic delocalization across RC and LH pigments results in a redistribution of absorption amplitudes that benefits the absorption cross section of the optical bands associated with the RC of several species. While we prove that this redistribution is robust to the microscopic details of the dephasing between these units in the purple bacterium Rhodospirillum rubrum, we are able to show that the redistribution witnesses a more fragile, but persistent, coherent population dynamics which directs excitations from the LH toward the RC units under incoherent illumination and physiological conditions. Even though the redirection does not seem to affect importantly the overall efficiency in photosynthesis, stochastic optimization allows us to delineate clear guidelines and develop simple analytic expressions in order to amplify the coherent redirection in artificial nanostructures.}, \%\%Address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, issn = {1948-7185}, doi = {10.1021/acs.jpclett.7b02714}, author = {Caycedo-Soler, Felipe and Schroeder, Christopher A. and Autenrieth, Caroline and Pick, Arne and Ghosh, Robin and Huelga, Susana F. and Plenio, Martin B.} } @article {ISI:000401585800006, title = {Realizing quantum advantage without entanglement in single-photon states}, journal = {NEW JOURNAL OF PHYSICS}, volume = {19}, year = {2017}, month = {MAY 16}, pages = {053009}, publisher = {IOP PUBLISHING LTD}, type = {Article}, abstract = {We propose an optical circuit for attaining quantum measurement advantage in a system that has no quantum entanglement. Our device produces symmetric two-qubit X-states with controllable anti-diagonal elements, and does not require entangled states as input. We discuss the use of this device in a two-qubit quantum game. When entanglement is absent, the maximum quantum advantage in this game is 1/3 bit. A slightly diminished quantum advantage, 0.311 bit, can be realized with a simplified transaction protocol.}, \%\%Address = {TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND}, keywords = {encoding process, entanglement, quantum advantage, quantum discord, single photons, X-states}, issn = {1367-2630}, doi = {10.1088/1367-2630/aa6cf4}, author = {Maldonado-Trapp, A. and Solano, Pablo and Hu, Anzi and Clark, Charles W.} } @article { ISI:000411973900008, title = {Rydberg optical Feshbach resonances in cold gases}, journal = {PHYSICAL REVIEW A}, volume = {96}, number = {3}, year = {2017}, month = {SEP 28}, issn = {2469-9926}, doi = {10.1103/PhysRevA.96.032719}, author = {Sandor, Nora and Gonzalez-Ferez, Rosario and Julienne, Paul S. and Pupillo, Guido} } @article { ISI:000415173000002, title = {Simultaneous, Full Characterization of a Single-Photon State}, journal = {PHYSICAL REVIEW X}, volume = {7}, number = {4}, year = {2017}, month = {NOV 15}, issn = {2160-3308}, doi = {10.1103/PhysRevX.7.041036}, author = {Thomay, Tim and Polyakov, Sergey V. and Gazzano, Olivier and Goldschmidt, Elizabeth and Eldredge, Zachary D. and Huber, Tobias and Loo, Vivien and Solomon, Glenn S.} } @article { ISI:000408826800004, title = {Skyrmion defects and competing singlet orders in a half-filled antiferromagnetic Kondo-Heisenberg model on the honeycomb lattice}, journal = {PHYSICAL REVIEW B}, volume = {96}, number = {12}, year = {2017}, month = {SEP 1}, issn = {2469-9950}, doi = {10.1103/PhysRevB.96.125101}, author = {Liu, Chia-Chuan and Goswami, Pallab and Si, Qimiao} } @article { ISI:000411572100009, title = {Spin-orbit coupling induced two-electron relaxation in silicon donor pairs}, journal = {PHYSICAL REVIEW B}, volume = {96}, number = {11}, year = {2017}, month = {SEP 25}, issn = {2469-9950}, doi = {10.1103/PhysRevB.96.115444}, author = {Song, Yang and S. Das Sarma} } @article { ISI:000413442100006, title = {Strong-coupling phases of the spin-orbit-coupled spin-1 Bose-Hubbard chain: Odd-integer Mott lobes and helical magnetic phases}, journal = {PHYSICAL REVIEW A}, volume = {96}, number = {4}, year = {2017}, month = {OCT 23}, issn = {2469-9926}, doi = {10.1103/PhysRevA.96.043622}, author = {Pixley, J. H. and Cole, William S. and Ian B Spielman and Rizzi, Matteo and S. Das Sarma} } @article {7871, title = {Super-radiance reveals infinite-range dipole interactions through a nanofiber}, journal = {Nature Communications}, volume = {8}, year = {2017}, pages = {1857}, abstract = {Atoms interact with each other through the electromagnetic field, creating collective states that can radiate faster or slower than a single atom, i.e., super- and sub-radiance. When the field is confined to one dimension it enables infinite-range atom{\textendash}atom interactions. Here we present the first report of infinite-range interactions between macroscopically separated atomic dipoles mediated by an optical waveguide. We use cold 87Rb atoms in the vicinity of a single-mode optical nanofiber (ONF) that coherently exchange evanescently coupled photons through the ONF mode. In particular, we observe super-radiance of a few atoms separated by hundreds of resonant wavelengths. The same platform allows us to measure sub-radiance, a rarely observed effect, presenting a unique tool for quantum optics. This result constitutes a proof of principle for collective behavior of macroscopically delocalized atomic states, a crucial element for new proposals in quantum information and many-body physics.

}, issn = {2041-1723}, doi = {10.1038/s41467-017-01994-3}, url = {https://doi.org/10.1038/s41467-017-01994-3}, author = {Solano, P and Barberis-Blostein, P and Fatemi, F K and Orozco, L A and Rolston, S L} } @article {7146, title = {Surface-dominated conduction up to 240K in the Kondo insulator SmB6 under strain}, journal = {Nature Materials}, volume = {advance online publication}, year = {2017}, month = {04/2017}, pages = {{\textendash}}, isbn = {1476-4660}, url = {http://dx.doi.org/10.1038/nmat4888}, author = {Stern, A. and Dzero, M. and Galitski, V. M. and Fisk, Z. and Xia, J.} } @article { ISI:000412247200006, title = {Temporal and spectral manipulations of correlated photons using a time lens}, journal = {PHYSICAL REVIEW A}, volume = {96}, number = {4}, year = {2017}, month = {OCT 4}, issn = {2469-9926}, doi = {10.1103/PhysRevA.96.043807}, author = {Mittal, Sunil and Orre, Venkata Vikram and Restelli, Alessandro and Salem, Reza and Goldschmidt, Elizabeth A. and Hafezi, Mohammad} } @article { ISI:000405362900007, title = {Theoretical study of the g factor and lifetime of the 6s6 p P-3(0) state of mercury}, journal = {PHYSICAL REVIEW A}, volume = {96}, number = {1}, year = {2017}, month = {JUL 13}, issn = {2469-9926}, doi = {10.1103/PhysRevA.96.012509}, author = {Porsev, S. G. and Safronova, U. I. and Safronova, M. S.} } @article { ISI:000408705200026, title = {Threshold Dynamics of a Semiconductor Single Atom Maser}, journal = {PHYSICAL REVIEW LETTERS}, volume = {119}, number = {9}, year = {2017}, month = {AUG 31}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.119.097702}, author = {Liu, Y. -Y. and Stehlik, J. and Eichler, C. and Mi, X. and Hartke, T. R. and Gullans, M. J. and Taylor, J. M. and Petta, J. R.} } @article {7261, title = {Time-reversal symmetry-breaking superconductivity in epitaxial bismuth/nickel bilayers}, journal = {Science Advances}, volume = {3}, year = {2017}, abstract = {Superconductivity that spontaneously breaks time-reversal symmetry (TRS) has been found, so far, only in a handful of three-dimensional (3D) crystals with bulk inversion symmetry. We report an observation of spontaneous TRS breaking in a 2D superconducting system without inversion symmetry: the epitaxial bilayer films of bismuth and nickel. The evidence comes from the onset of the polar Kerr effect at the superconducting transition in the absence of an external magnetic field, detected by the ultrasensitive loop-less fiber-optic Sagnac interferometer. Because of strong spin-orbit interaction and lack of inversion symmetry in a Bi/Ni bilayer, superconducting pairing cannot be classified as singlet or triplet. We propose a theoretical model where magnetic fluctuations in Ni induce the superconducting pairing of the orbital symmetry between the electrons in Bi. In this model, the order parameter spontaneously breaks the TRS and has a nonzero phase winding number around the Fermi surface, thus making it a rare example of a 2D topological superconductor.

}, doi = {10.1126/sciadv.1602579}, url = {http://advances.sciencemag.org/content/3/3/e1602579}, author = {Gong, Xinxin and Kargarian, Mehdi and Stern, Alex and Yue, Di and Zhou, Hexin and Jin, Xiaofeng and Galitski, Victor M. and Yakovenko, Victor M. and Xia, Jing} } @article {ISI:000396271900006, title = {Topological spin ordering via Chern-Simons superconductivity}, journal = {PHYSICAL REVIEW B}, volume = {95}, number = {9}, year = {2017}, month = {MAR 15}, pages = {094511}, abstract = {We use the Chern-Simons (CS) fermion representation of s = 1/2 spin operators to construct topological, long-range magnetically ordered states of interacting two-dimensional (2D) quantum spin models. We show that the fermion-fermion interactions mediated by the dynamic CS flux attachment may give rise to Cooper pairing of the fermions. Specifically, in an XY model on the honeycomb lattice, this construction leads to a {\textquoteleft}{\textquoteleft}CS superconductor{{\textquoteright}{\textquoteright}}, which belongs to a topologically nontrivial in 2D symmetry class DIII, with particle-hole and time-reversal symmetries. It is shown that in the original spin language, this state corresponds to a symmetry protected topological state, which coexists with a magnetic long-range order. We discuss physical manifestations of the topological character of the corresponding state.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.95.094511}, author = {Sedrakyan, Tigran A. and Galitski, Victor M. and Kamenev, Alex} } @article {ISI:000401997600008, title = {Transport in superconductor-normal metal-superconductor tunneling structures: Spinful p-wave and spin-orbit-coupled topological wires}, journal = {PHYSICAL REVIEW B}, volume = {95}, number = {17}, year = {2017}, month = {MAY 22}, pages = {174515}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We theoretically study transport properties of voltage-biased one-dimensional superconductor-normal metal-superconductor tunnel junctions with arbitrary junction transparency where the superconductors can have trivial or nontrivial topology. Motivated by recent experimental efforts on Majorana properties of superconductor-semiconductor hybrid systems, we consider two explicit models for topological superconductors: (i) spinful p-wave, and (ii) spin-split spin-orbit-coupled s-wave. We provide a comprehensive analysis of the zero-temperature dc current I and differential conductance dI/dV of voltage-biased junctions with or without Majorana zero modes (MZMs). The presence of an MZM necessarily gives rise to two tunneling conductance peaks at voltages eV = +/-Delta(lead), i.e., the voltage at which the superconducting gap edge of the lead aligns with the MZM. We find that the MZM conductance peak probed by a superconducting lead without a BCS singularity has a nonuniversal value, which decreases with decreasing junction transparency. This is in contrast to the MZM tunneling conductance measured by a superconducting lead with a BCS singularity, where the conductance peak in the tunneling limit takes the quantized value GM = (4 - pi)2e(2)/h independent of the junction transparency. We also discuss the {\textquoteleft}{\textquoteleft}subharmonic gap structure{{\textquoteright}{\textquoteright}}, a consequence of multiple Andreev reflections, in the presence and absence of MZMs. Finally, we show that for finite-energy Andreev bound states (ABSs), the conductance peaks shift away from the gap bias voltage eV = +/-Delta(lead) to a larger value set by the ABSs energy. Our work should have important implications for the extensive current experimental efforts toward creating topological superconductivity and MZMs in semiconductor nanowires proximity coupled to ordinary s-wave superconductors.}, \%\%Address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA

}, issn = {2469-9950}, doi = {10.1103/PhysRevB.95.174515}, author = {Setiawan, F. and Cole, William S. and Sau, Jay D. and S. Das Sarma} } @article { ISI:000411162600002, title = {Transport properties across the many-body localization transition in quasiperiodic and random systems}, journal = {PHYSICAL REVIEW B}, volume = {96}, number = {10}, year = {2017}, month = {SEP 19}, issn = {2469-9950}, doi = {10.1103/PhysRevB.96.104205}, author = {Setiawan, F. and Deng, Dong-Ling and Pixley, J. H.} } @article { ISI:000411773400029, title = {Visible spectra of highly charged holmium ions observed with a compact electron beam ion trap}, journal = {NUCLEAR INSTRUMENTS \& METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS}, volume = {408}, year = {2017}, note = {18th International Conference on the Physics of Highly Charged Ions (HCI), Jan Kochanowski Univ, Kielce, POLAND, SEP 11-16, 2016}, month = {OCT 1}, pages = {118-121}, issn = {0168-583X}, doi = {10.1016/j.nimb.2017.03.135}, author = {Nakajima, Takayuki and Okada, Kunihiro and Wada, Michiharu and Dzuba, Vladimir A. and Safronova, Marianna S. and Safronova, Ulyana I. and Ohmae, Noriaki and Katori, Hidetoshi and Nakamura, Nobuyuki} } @article { ISI:000415687200020, title = {Z(3) Parafermionic Zero Modes without Andreev Backscattering from the 2/3 Fractional Quantum Hall State}, journal = {PHYSICAL REVIEW LETTERS}, volume = {119}, number = {21}, year = {2017}, month = {NOV 20}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.119.217701}, author = {Alavirad, Yahya and Clarke, David and Nag, Amit and Sau, Jay D.} } @article { ISI:000368473600004, title = {Anomalous supersolidity in a weakly interacting dipolar Bose mixture on a square lattice}, journal = {PHYSICAL REVIEW A}, volume = {93}, number = {1}, year = {2016}, month = {JAN 19}, issn = {1050-2947}, doi = {10.1103/PhysRevA.93.011605}, author = {Wilson, Ryan M. and Shirley, Wilbur E. and Natu, Stefan S.} } @article { ISI:000376250800005, title = {Ca3P2 and other topological semimetals with line nodes and drumhead surface states}, journal = {PHYSICAL REVIEW B}, volume = {93}, number = {20}, year = {2016}, month = {MAY 17}, issn = {2469-9950}, doi = {10.1103/PhysRevB.93.205132}, author = {Chan, Y. -H. and Chiu, Ching-Kai and Chou, M. Y. and Schnyder, Andreas P.} } @article { ISI:000371398000004, title = {Calculation for polar Kerr effect in high-temperature cuprate superconductors}, journal = {PHYSICAL REVIEW B}, volume = {93}, number = {7}, year = {2016}, month = {FEB 29}, issn = {2469-9950}, doi = {10.1103/PhysRevB.93.075156}, author = {Sharma, Girish and Tewari, Sumanta and Goswami, Pallab and Yakovenko, Victor M. and Chakravarty, Sudip} } @article {ISI:000372407200003, title = {Characterization of the local charge environment of a single quantum dot via resonance fluorescence}, journal = {PHYSICAL REVIEW B}, volume = {93}, number = {11}, year = {2016}, month = {MAR 14}, pages = {115307}, chapter = {115307}, issn = {2469-9950}, doi = {10.1103/PhysRevB.93.115307}, author = {Chen, Disheng and Lander, Gary R. and Krowpman, Kyle S. and Solomon, Glenn S. and Flagg, Edward B.} } @article { ISI:000383053400001, title = {Classification of topological quantum matter with symmetries}, journal = {REVIEWS OF MODERN PHYSICS}, volume = {88}, number = {3}, year = {2016}, month = {AUG 31}, issn = {0034-6861}, doi = {10.1103/RevModPhys.88.035005}, author = {Chiu, Ching-Kai and Teo, Jeffrey C. Y. and Schnyder, Andreas P. and Ryu, Shinsei} } @article { ISI:000375997500002, title = {Coherence and degree of time-bin entanglement from quantum dots}, journal = {PHYSICAL REVIEW B}, volume = {93}, number = {20}, year = {2016}, month = {MAY 12}, pages = {201301}, issn = {2469-9950}, doi = {10.1103/PhysRevB.93.201301}, author = {Huber, Tobias and Ostermann, Laurin and Prilmueller, Maximilian and Solomon, Glenn S. and Ritsch, Helmut and Weihs, Gregor and Predojevic, Ana} } @article { ISI:000378910200001, title = {Continuous and discontinuous topological quantum phase transitions}, journal = {PHYSICAL REVIEW B}, volume = {94}, number = {4}, year = {2016}, month = {JUL 1}, pages = {041101}, issn = {2469-9950}, doi = {10.1103/PhysRevB.94.041101}, author = {Roy, Bitan and Goswami, Pallab and Sau, Jay D.} } @article { ISI:000376250800002, title = {Dirty Weyl semimetals: Stability, phase transition, and quantum criticality}, journal = {PHYSICAL REVIEW B}, volume = {93}, number = {20}, year = {2016}, month = {MAY 17}, issn = {2469-9950}, doi = {10.1103/PhysRevB.93.201302}, author = {Bera, Soumya and Sau, Jay D. and Roy, Bitan} } @article {4424, title = {Doublon dynamics and polar molecule production in an optical lattice}, journal = {Nature Communications}, volume = {7}, year = {2016}, month = {04/2016}, pages = {11279}, doi = {10.1038/ncomms11279}, author = {Covey, Jacob P and Moses, Stephen A and G{\"a}rttner, Martin and Safavi-Naini, Arghavan and Miecnikowski, Matthew T and Fu, Zhengkun and Schachenmayer, Johannes and Julienne, Paul S and Rey, Ana M. and Jin, Deborah S and Ye, Jun} } @article { ISI:000372799400003, title = {Drumhead surface states and topological nodal-line fermions in TlTaSe2}, journal = {PHYSICAL REVIEW B}, volume = {93}, number = {12}, year = {2016}, month = {MAR 28}, issn = {2469-9950}, doi = {10.1103/PhysRevB.93.121113}, author = {Bian, Guang and Chang, Tay-Rong and Zheng, Hao and Velury, Saavanth and Xu, Su-Yang and Neupert, Titus and Chiu, Ching-Kai and Huang, Shin-Ming and Sanchez, Daniel S. and Belopolski, Ilya and Alidoust, Nasser and Chen, Peng-Jen and Chang, Guoqing and Bansil, Arun and Jeng, Horng-Tay and Lin, Hsin and Hasan, M. Zahid} } @article {6261, title = {Effects of photo-neutralization on the emission properties of quantum dots}, journal = {Opt. Express}, volume = {24}, year = {2016}, month = {Sep}, pages = {21794{\textendash}21801}, abstract = {In this paper we investigate the coherence properties of a quantum dot used as photon pair source, under two-photon resonant excitation in combination with an additional photo-neutralization laser. The photo-neutralization increases the efficiency of the excitation process and thus, the brightness of the source, by a factor of approximately 1.5 for biexciton-exciton pairs. This enhancement does not degrade the relevant coherences in the system; neither the single photon coherence time, nor the coherence of the excitation process.

}, keywords = {-wire and -dot devices, and noise, Fluctuations, Quantum optics, Quantum-well, relaxations}, doi = {10.1364/OE.24.021794}, url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-24-19-21794}, author = {Tobias Huber and Ana Predojevi{\'c} and Glenn S. Solomon and Gregor Weihs} } @article {ISI:000385239800002, title = {Engineering large Stark shifts for control of individual clock state qubits}, journal = {PHYSICAL REVIEW A}, volume = {94}, number = {4}, year = {2016}, month = {OCT 7}, pages = {042308}, issn = {2469-9926}, doi = {10.1103/PhysRevA.94.042308}, author = {Lee, A. C. and Smith, J. and Richerme, P. and Neyenhuis, B. and Hess, P. W. and Zhang, J. and Monroe, C.} } @article { ISI:000379647900004, title = {Fast control of semiconductor qubits beyond the rotating-wave approximation}, journal = {PHYSICAL REVIEW A}, volume = {94}, number = {1}, year = {2016}, month = {JUL 14}, issn = {2469-9926}, doi = {10.1103/PhysRevA.94.012321}, author = {Song, Yang and Kestner, J. P. and Wang, Xin and S. Das Sarma} } @article {4468, title = {Geometrical Pumping with a Bose-Einstein Condensate}, journal = {Phys. Rev. Lett.}, volume = {116}, year = {2016}, month = {05/2016}, pages = {200402}, abstract = {We realized a quantum geometric {\textquotedblleft}charge{\textquotedblright} pump for a Bose-Einstein condensate (BEC) in the lowest Bloch band of a novel bipartite magnetic lattice. Topological charge pumps in filled bands yield quantized pumping set by the global{\textemdash}topological{\textemdash}properties of the bands. In contrast, our geometric charge pump for a BEC occupying just a single crystal momentum state exhibits nonquantized charge pumping set by local{\textemdash}geometrical{\textemdash}properties of the band structure. Like topological charge pumps, for each pump cycle we observed an overall displacement (here, not quantized) and a temporal modulation of the atomic wave packet{\textquoteright}s position in each unit cell, i.e., the polarization.

}, doi = {10.1103/PhysRevLett.116.200402}, url = {http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.200402}, author = {Lu, H and Schemmer, M and Aycock, L M and Genkina, D and Sugawa, S and Ian B Spielman} } @article {6241, title = {Holography with a neutron interferometer}, journal = {Opt. Express}, volume = {24}, year = {2016}, month = {Oct}, pages = {22528{\textendash}22535}, abstract = {We use a Mach-Zehnder interferometer to perform neutron holography of a spiral phase plate. The object beam passes through a spiral phase plate, acquiring the phase twist characteristic of orbital angular momentum states. The reference beam passes through a fused silica prism, acquiring a linear phase gradient. The resulting hologram is a fork dislocation image, which could be used to reconstruct neutron beams with various orbital angular momenta. This work paves the way for novel applications of neutron holography, diffraction and imaging.

}, keywords = {Digital holography, Interferometry, Optical vortices, Propagation}, doi = {10.1364/OE.24.022528}, url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-24-20-22528}, author = {Dusan Sarenac and Michael G. Huber and Benjamin Heacock and Muhammad Arif and Charles W. Clark and David G. Cory and Chandra B. Shahi and Dmitry A. Pushin} } @article { ISI:000380100300003, title = {How to infer non-Abelian statistics and topological visibility from tunneling conductance properties of realistic Majorana nanowires}, journal = {PHYSICAL REVIEW B}, volume = {94}, number = {3}, year = {2016}, month = {JUL 20}, pages = {035143}, issn = {2469-9950}, doi = {10.1103/PhysRevB.94.035143}, author = {S. Das Sarma and Nag, Amit and Sau, Jay D.} } @article {ISI:000369402400001, title = {Interaction-driven exotic quantum phases in spin-orbit-coupled spin-1 bosons}, journal = {PHYSICAL REVIEW B}, volume = {93}, number = {8}, year = {2016}, month = {FEB 1}, pages = {081101}, issn = {2469-9950}, doi = {10.1103/PhysRevB.93.081101}, author = {Pixley, J. H. and Natu, Stefan S. and Ian B Spielman and S. Das Sarma} } @article { ISI:000373117500001, title = {Interplanar coupling-dependent magnetoresistivity in high-purity layered metals}, journal = {NATURE COMMUNICATIONS}, volume = {7}, year = {2016}, month = {MAR}, issn = {2041-1723}, doi = {10.1038/ncomms10903}, author = {Kikugawa, N. and Goswami, P. and Kiswandhi, A. and Choi, E. S. and Graf, D. and Baumbach, R. E. and Brooks, J. S. and Sugii, K. and Iida, Y. and Nishio, M. and Uji, S. and Terashima, T. and Rourke, P. M. C. and Hussey, N. E. and Takatsu, H. and Yonezawa, S. and Maeno, Y. and Balicas, L.} } @article {ISI:000379697900007, title = {Magic wavelengths, matrix elements, polarizabilities, and lifetimes of Cs}, journal = {PHYSICAL REVIEW A}, volume = {94}, number = {1}, year = {2016}, month = {JUL 6}, pages = {012505}, abstract = {Motivated by recent interest in their applications, we report a systematic study of Cs atomic properties calculated by a high-precision relativistic all-order method. Excitation energies, reduced matrix elements, transition rates, and lifetimes are determined for levels with principal quantum numbers n <= 12 and orbital angular momentum quantum numbers l <= 3. Recommended values and estimates of uncertainties are provided for a number of electric-dipole transitions and the electric dipole polarizabilities of the ns, np, and nd states. We also report a calculation of the electric quadrupole polarizability of the ground state. We display the dynamic polarizabilities of the 6s and 7p states for optical wavelengths between 1160 and 1800 nm and identify corresponding magic wavelengths for the 6s - 7p(1/2) and 6s - 7p(3/2) transitions. The values of relevant matrix elements needed for polarizability calculations at other wavelengths are provided.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.94.012505}, author = {Safronova, M. S. and Safronova, U. I. and Clark, Charles W.} } @article {4390, title = {Magnetic phases of spin-1 spin{\textendash}orbit-coupled Bose gases}, journal = {Nature Communications}, volume = {7}, year = {2016}, month = {03/2016}, pages = {10897}, abstract = {Phases of matter are characterized by order parameters describing the type and degree of order in a system. Here we experimentally explore the magnetic phases present in a near-zero temperature spin-1 spin{\textendash}orbit-coupled atomic Bose gas and the quantum phase transitions between these phases. We observe ferromagnetic and unpolarized phases, which are stabilized by spin{\textendash}orbit coupling{\textquoteright}s explicit locking between spin and motion. These phases are separated by a critical curve containing both first- and second-order transitions joined at a tricritical point. The first-order transition, with observed width as small as h {\texttimes} 4\ Hz, gives rise to long-lived metastable states. These measurements are all in agreement with theory.

}, doi = {10.1038/ncomms10897}, author = {Daniel L Campbell and Ryan M. Price and Andika Putra and Ana Vald{\'e}s-Curiel and Dimitrios Trypogeorgos and Ian B Spielman} } @article {4632, title = {Many-body localization in a quantum simulator with programmable random disorder}, journal = {Nature Physics}, year = {2016}, month = {06/2016}, doi = {10.1038/nphys3783}, url = {http://www.nature.com/nphys/journal/vaop/ncurrent/full/nphys3783.html}, author = {Smith, J and Lee, A and Richerme, P and Neyenhuis, B and Hess, P W and Hauke, P and Heyl, M and Huse, D A and Monroe, C} } @article {ISI:000388280000002, title = {Measurement Protocol for the Entanglement Spectrum of Cold Atoms}, journal = {PHYSICAL REVIEW X}, volume = {6}, number = {4}, year = {2016}, month = {NOV 17}, pages = {041033}, abstract = {Entanglement, and, in particular, the entanglement spectrum, plays a major role in characterizing many-body quantum systems. While there has been a surge of theoretical works on the subject, no experimental measurement has been performed to date because of the lack of an implementable measurement scheme. Here, we propose a measurement protocol to access the entanglement spectrum of many-body states in experiments with cold atoms in optical lattices. Our scheme effectively performs a Ramsey spectroscopy of the entanglement Hamiltonian and is based on the ability to produce several copies of the state under investigation, together with the possibility to perform a global swap gate between two copies conditioned on the state of an auxiliary qubit. We show how the required conditional swap gate can be implemented with cold atoms, either by using Rydberg interactions or coupling the atoms to a cavity mode. We illustrate these ideas on a simple (extended) Bose-Hubbard model where such a measurement protocol reveals topological features of the Haldane phase.}, issn = {2160-3308}, doi = {10.1103/PhysRevX.6.041033}, author = {Pichler, Hannes and Zhu, Guanyu and Seif, Alireza and Zoller, Peter and Hafezi, Mohammad} } @article {ISI:000372462400001, title = {Minimally destructive, Doppler measurement of a quantized flow in a ring-shaped Bose-Einstein condensate}, journal = {NEW JOURNAL OF PHYSICS}, volume = {18}, year = {2016}, month = {FEB 1}, pages = {025001}, issn = {1367-2630}, doi = {10.1088/1367-2630/18/2/025001}, author = {Kumar, A. and Anderson, N. and Phillips, W. D. and Eckel, S. and Campbell, G. K. and Stringari, S.} } @article {ISI:000383412100015, title = {Nanostructure-Induced Distortion in Single-Emitter Microscopy}, journal = {NANO LETTERS}, volume = {16}, number = {9}, year = {2016}, month = {SEP}, pages = {5415-5419}, issn = {1530-6984}, doi = {10.1021/acs.nanolett.6b01708}, author = {Lim, Kangmook and Ropp, Chad and Barik, Sabyasachi and Fourkas, John and Shapiro, Benjamin and Waks, Edo} } @article { ISI:000368295000003, title = {Nernst and magnetothermal conductivity in a lattice model of Weyl fermions}, journal = {PHYSICAL REVIEW B}, volume = {93}, number = {3}, year = {2016}, month = {JAN 13}, issn = {1098-0121}, doi = {10.1103/PhysRevB.93.035116}, author = {Sharma, Girish and Goswami, Pallab and Tewari, Sumanta} } @article {4436, title = {A Practical Phase Gate for Producing Bell Violations in Majorana Wires}, journal = {Phys. Rev. X}, volume = {6}, year = {2016}, month = {04/2016}, pages = {021005}, doi = {10.1103/PhysRevX.6.021005}, author = {Clarke, D J and Sau, J D and S. Das Sarma} } @article {ISI:000374560300010, title = {Projected Dipole Moments of Individual Two-Level Defects Extracted Using Circuit Quantum Electrodynamics}, journal = {PHYSICAL REVIEW LETTERS}, volume = {116}, number = {16}, year = {2016}, month = {APR 22}, pages = {167002}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.116.167002}, author = {Sarabi, B. and Ramanayaka, A. N. and Burin, A. L. and Wellstood, F. C. and Osborn, K. D.} } @article {ISI:000390349100003, title = {Proximity effect and Majorana bound states in clean semiconductor nanowires coupled to disordered superconductors}, journal = {PHYSICAL REVIEW B}, volume = {94}, number = {14}, year = {2016}, month = {OCT 27}, pages = {140505}, abstract = {We model a semiconductor wire with strong spin-orbit coupling which is proximity-coupled to a superconductor with chemical potential disorder. When tunneling at the semiconductor-superconductor interface is very weak, disorder in the superconductor does not affect the induced superconductivity nor, therefore, the effective topological superconductivity that emerges above a critical magnetic field. Here we demonstrate, nonperturbatively, how this result breaks down with stronger proximity coupling by obtaining the low-energy (i.e., subgap) excitation spectrum through direct numerical diagonalization of an appropriate Bogoliubov-de Gennes Hamiltonian. We find that the combination of strong proximity coupling and superconductor disorder suppresses the (nontopological) induced gap at zero magnetic field by disordering the induced pair potential. In the topological superconducting phase at large magnetic field, strong proximity coupling also reduces the localization length of Majorana bound states, such that the induced disorder eliminates the topological gap while bulk zero modes proliferate, even for short wires.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.94.140505}, author = {Cole, William S. and Sau, Jay D. and S. Das Sarma} } @article {ISI:000374726000029, title = {QUANTUM CONNECTIONS}, journal = {SCIENTIFIC AMERICAN}, volume = {314}, number = {5}, year = {2016}, month = {MAY}, pages = {50-57}, issn = {0036-8733}, author = {Monroe, Christopher R. and Schoelkopf, Robert J. and Lukin, Mikhail D.} } @article {4154, title = {A quantum phase switch between a single solid-state spin and a photon}, journal = {Nature Nanotechnology}, volume = {11}, year = {2016}, month = {02/2016}, pages = {539}, doi = {10.1038/nnano.2015.334}, url = {http://www.nature.com/nnano/journal/vaop/ncurrent/full/nnano.2015.334.html}, author = {Sun, Shuo and Kim, Hyochul and Solomon, Glenn S. and Waks, Edo} } @article {4416, title = {Radio Frequency Tunable Oscillator Device Based on a SmB6 Microcrystal}, journal = {Phys. Rev. Lett.}, volume = {116}, year = {2016}, month = {04/2016}, pages = {166603}, doi = {10.1103/PhysRevLett.116.166603}, author = {Stern, Alex and Efimkin, Dmitry K. and Galitski, Victor and Fisk, Zachary and Xia, Jing} } @article { ISI:000367835400023, title = {Raman coherence in a circuit quantum electrodynamics lambda system}, journal = {NATURE PHYSICS}, volume = {12}, number = {1}, year = {2016}, month = {JAN}, pages = {75-U104}, issn = {1745-2473}, doi = {10.1038/NPHYS3537}, author = {Novikov, S. and Sweeney, T. and Robinson, J. E. and Premaratne, S. P. and Suri, B. and Wellstood, F. C. and Palmer, B. S.} } @article {ISI:000373727800001, title = {Rashba realization: Raman with RF}, journal = {NEW JOURNAL OF PHYSICS}, volume = {18}, year = {2016}, month = {APR 1}, pages = {033035}, issn = {1367-2630}, doi = {10.1088/1367-2630/18/3/033035}, author = {Campbell, D. L. and Ian B Spielman} } @article {ISI:000390246200008, title = {Real-space mean-field theory of a spin-1 Bose gas in synthetic dimensions}, journal = {PHYSICAL REVIEW A}, volume = {94}, number = {6}, year = {2016}, month = {DEC 15}, pages = {063613}, abstract = {The internal degrees of freedom provided by ultracold atoms provide a route for realizing higher dimensional physics in systems with limited spatial dimensions. Nonspatial degrees of freedom in these systems are dubbed {\textquoteleft}{\textquoteleft}synthetic dimensions.{{\textquoteright}{\textquoteright}} This connection is useful from an experimental standpoint but complicated by the fact that interactions alter the condensate ground state. Here we use the Gross-Pitaevskii equation to study the ground-state properties of a spin-1 Bose gas under the combined influence of an optical lattice, spatially varying spin-orbit coupling, and interactions at the mean-field level. The associated phases depend on the sign of the spin-dependent interaction parameter and the strength of the spin-orbit field. We find {\textquoteleft}{\textquoteleft}charge{{\textquoteright}{\textquoteright}}- and spin-density-wave phases which are directly related to helical spin order in real space and affect the behavior of edge currents in the synthetic dimension. We determine the resulting phase diagram as a function of the spin-orbit coupling and spin-dependent interaction strength, considering both attractive (ferromagnetic) and repulsive (polar) spin-dependent interactions, and we provide a direct comparison of our results with the noninteracting case. Our findings are applicable to current and future experiments, specifically with Rb-87, Li-7, K-41, and Na-23.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.94.063613}, author = {Hurst, Hilary M. and Wilson, Justin H. and Pixley, J. H. and Ian B Spielman and Natu, Stefan S.} } @article {ISI:000384068400002, title = {Role of boundary conditions, topology, and disorder in the chiral magnetic effect in Weyl semimetals}, journal = {PHYSICAL REVIEW B}, volume = {94}, number = {11}, year = {2016}, month = {SEP 27}, pages = {115160}, issn = {2469-9950}, doi = {10.1103/PhysRevB.94.115160}, author = {Alavirad, Yahya and Sau, Jay D.} } @article {ISI:000388814500011, title = {Self-organization of atoms coupled to a chiral reservoir}, journal = {PHYSICAL REVIEW A}, volume = {94}, number = {5}, year = {2016}, month = {NOV 29}, pages = {053855}, abstract = {Tightly confined modes of light, as in optical nanofibers or photonic crystal waveguides, can lead to large optical coupling in atomic systems, which mediates long-range interactions between atoms. These one-dimensional systems can naturally possess couplings that are asymmetric between modes propagating in different directions. Strong long-range interaction among atoms via these modes can drive them to a self-organized periodic distribution. In this paper, we examine the self-organizing behavior of atoms in one dimension coupled to a chiral reservoir. We determine the solution to the equations of motion in different parameter regimes, relative to both the detuning of the pump laser that initializes the atomic dipole-dipole interactions and the degree of reservoir chirality. In addition, we calculate possible experimental signatures such as reflectivity from self-organized atoms and motional sidebands.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.94.053855}, author = {Eldredge, Zachary and Solano, Pablo and Chang, Darrick and Gorshkov, Alexey V.} } @article {ISI:000390255800014, title = {Semisynthetic zigzag optical lattice for ultracold bosons}, journal = {PHYSICAL REVIEW A}, volume = {94}, number = {6}, year = {2016}, month = {DEC 22}, pages = {063632}, abstract = {We propose a cold-atom realization of a zigzag ladder. The two legs of the ladder correspond to a {\textquoteleft}{\textquoteleft}synthetic{{\textquoteright}{\textquoteright}} dimension given by two internal (spin) states of the atoms, so that tunneling between them can be realized as a laser-assisted process. The zigzag geometry is achieved by employing a spin-dependent optical lattice with the site position depending on the internal atomic state, i.e., on the ladder{\textquoteright}s leg. The lattice offers a possibility to tune the single-particle dispersion from a double-well to a single-minimum configuration. In contrast to previously considered semisynthetic lattices with a square geometry, the tunneling in the synthetic dimension is accompanied by spatial displacements of atoms. Therefore, the atom-atom interactions are nonlocal and act along the diagonal (semisynthetic) direction. We investigate the ground-state properties of the system for the case of strongly interacting bosons. In particular, we find that the interplay between the frustration induced by the magnetic field and the interactions gives rise to an interesting gapped phase at fractional filling factors corresponding to one particle per magnetic unit cell.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.94.063632}, author = {Anisimovas, E. and Raciunas, M. and Straeter, C. and Eckardt, A. and Ian B Spielman and Juzeliunas, G.} } @article {ISI:000379697300009, title = {Single-shot optical readout of a quantum bit using cavity quantum electrodynamics}, journal = {PHYSICAL REVIEW A}, volume = {94}, number = {1}, year = {2016}, month = {JUL 5}, pages = {012307}, issn = {2469-9926}, doi = {10.1103/PhysRevA.94.012307}, author = {Sun, Shuo and Waks, Edo} } @article {ISI:000381468300006, title = {Sisyphus Thermalization of Photons in a Cavity-Coupled Double Quantum Dot}, journal = {PHYSICAL REVIEW LETTERS}, volume = {117}, number = {5}, year = {2016}, month = {JUL 25}, pages = {056801}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.117.056801}, author = {Gullans, M. J. and Stehlik, J. and Liu, Y. -Y. and Eichler, C. and Petta, J. R. and Taylor, J. M.} } @article {ISI:000384214600001, title = {Synthetic gauge potentials for ultracold neutral atoms}, journal = {JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS}, volume = {48}, number = {18}, year = {2016}, month = {SEP 28}, pages = {183001}, issn = {0953-4075}, doi = {10.1088/0953-4075/49/18/183001}, author = {Lin, Yu-Ju and Ian B Spielman} } @article { ISI:000367187000009, title = {Topological defect lasers}, journal = {JOURNAL OF OPTICS}, volume = {18}, number = {1}, year = {2016}, month = {JAN}, issn = {2040-8978}, doi = {10.1088/2040-8978/18/1/014005}, author = {Knitter, Sebastian and Liew, Seng Fatt and Xiong, Wen and Guy, Mikhael I. and Solomon, Glenn S. and Cao, Hui} } @article {ISI:000379747100019, title = {Toward optical quantum information processing with quantum dots coupled to microstructures {[}Invited]}, journal = {JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS}, volume = {33}, number = {7}, year = {2016}, month = {JUL 1}, pages = {C160}, issn = {0740-3224}, doi = {10.1364/JOSAB.33.00C160}, author = {Gazzano, Olivier and Solomon, Glenn S.} } @article {ISI:000387905800007, title = {Vortex nucleation in a Bose-Einstein condensate: from the inside out}, journal = {NEW JOURNAL OF PHYSICS}, volume = {18}, year = {2016}, month = {NOV 4}, pages = {113009}, abstract = {We observed a new mechanism for vortex nucleation in Bose-Einstein condensates (BECs) subject to synthetic magnetic fields. We made use of a strong synthetic magnetic field initially localized between a pair of merging BECs to rapidly create vortices in the bulk of the merged condensate. Unlike previous implementations and in agreement with our Gross-Pitaevskii equation simulations, our dynamical process rapidly injects vortices into our system{\textquoteright}s bulk, and with initial number in excess of the system{\textquoteright}s equilibrium vortex number.}, issn = {1367-2630}, doi = {10.1088/1367-2630/18/11/113009}, author = {Price, R. M. and Trypogeorgos, D. and Campbell, D. L. and Putra, A. and Valdes-Curiel, A. and Ian B Spielman} } @article { ISI:000356221000001, title = {Accurate and Robust Unitary Transformations of a High-Dimensional Quantum System}, journal = {PHYSICAL REVIEW LETTERS}, volume = {114}, number = {24}, year = {2015}, month = {JUN 16}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.114.240401}, author = {Anderson, B. E. and Sosa-Martinez, H. and Riofrio, C. A. and Deutsch, Ivan H. and Jessen, Poul S.} } @article {ISI:000352613700024, title = {Assembling a complex quantum ensemble}, journal = {SCIENCE}, volume = {348}, number = {6231}, year = {2015}, month = {APR 10}, pages = {185-186}, issn = {0036-8075}, doi = {10.1126/science.aaa8070}, author = {Ian B Spielman} } @article { ISI:000355720600004, title = {Assembling Fibonacci anyons from a Z(3) parafermion lattice model}, journal = {PHYSICAL REVIEW B}, volume = {91}, number = {23}, year = {2015}, month = {JUN 8}, issn = {1098-0121}, doi = {10.1103/PhysRevB.91.235112}, author = {Stoudenmire, E. M. and Clarke, David J. and Mong, Roger S. K. and Alicea, Jason} } @conference { ISI:000354845400009, title = {Atomic Polarizabilities}, booktitle = {PROCEEDINGS OF THE INTERNATIONAL CONFERENCE OF COMPUTATIONAL METHODS IN SCIENCES AND ENGINEERING 2010 (ICCMSE-2010)}, series = {AIP Conference Proceedings}, volume = {1642}, year = {2015}, note = {International Conference of Computational Methods in Sciences and Engineering (ICCMSE), Kos, GREECE, OCT 03-08, 2010}, pages = {81-89}, isbn = {978-0-7354-1282-8}, issn = {0094-243X}, doi = {10.1063/1.4906633}, author = {Safronova, M. S. and Mitroy, J. and Clark, Charles W. and Kozlov, M. G.}, editor = {Simos, TE and Maroulis, G} } @article { ISI:000361376200011, title = {Bound States of a Ferromagnetic Wire in a Superconductor}, journal = {PHYSICAL REVIEW LETTERS}, volume = {115}, number = {12}, year = {2015}, month = {SEP 18}, pages = {127003}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.115.127003}, author = {Sau, Jay D. and Brydon, P. M. R.} } @article { ISI:000366490300001, title = {Broad universal Feshbach resonances in the chaotic spectrum of dysprosium atoms}, journal = {PHYSICAL REVIEW A}, volume = {92}, number = {6}, year = {2015}, month = {DEC 14}, issn = {1050-2947}, doi = {10.1103/PhysRevA.92.060702}, author = {Maier, T. and Ferrier-Barbut, I. and Kadau, H. and Schmitt, M. and Wenzel, M. and Wink, C. and Pfau, T. and Jachymski, K. and Julienne, P. S.} } @article { ISI:000348119700005, title = {Broadband measurement of coating thermal noise in rigid Fabry-Perot cavities}, journal = {METROLOGIA}, volume = {52}, number = {1}, year = {2015}, month = {FEB}, issn = {0026-1394}, doi = {10.1088/0026-1394/52/1/17}, author = {Chalermsongsak, Tara and Seifert, Frank and Hall, Evan D. and Arai, Koji and Gustafson, Eric K. and Adhikari, Rana X.} } @article { ISI:000364471100002, title = {Bulk disorder in the superconductor affects proximity-induced topological superconductivity}, journal = {PHYSICAL REVIEW B}, volume = {92}, number = {17}, year = {2015}, month = {NOV 12}, pages = {174512}, issn = {1098-0121}, doi = {10.1103/PhysRevB.92.174512}, author = {Hui, Hoi-Yin and Sau, Jay D. and S. Das Sarma} } @article { ISI:000365774000005, title = {Capacitively coupled singlet-triplet qubits in the double charge resonant regime}, journal = {PHYSICAL REVIEW B}, volume = {92}, number = {23}, year = {2015}, month = {DEC 1}, pages = {235301}, issn = {1098-0121}, doi = {10.1103/PhysRevB.92.235301}, author = {Srinivasa, V. and Taylor, J. M.} } @article { ISI:000353839100036, title = {Cavity quantum electrodynamics using a near-resonance two-level system: Emergence of the Glauber state}, journal = {APPLIED PHYSICS LETTERS}, volume = {106}, number = {17}, year = {2015}, month = {APR 27}, issn = {0003-6951}, doi = {10.1063/1.4918775}, author = {Sarabi, B. and Ramanayaka, A. N. and Burin, A. L. and Wellstood, F. C. and Osborn, K. D.} } @article { ISI:000357750100019, title = {CI-MBPT: A package of programs for relativistic atomic calculations based on a method combining configuration interaction and many-body perturbation theory}, journal = {COMPUTER PHYSICS COMMUNICATIONS}, volume = {195}, year = {2015}, month = {OCT}, pages = {199-213}, issn = {0010-4655}, doi = {10.1016/j.cpc.2015.05.007}, author = {Kozlov, M. G. and Porsev, S. G. and Safronova, M. S. and Tupitsyn, I. I.} } @article { ISI:000352142300002, title = {Cluster extended dynamical mean-field approach and unconventional superconductivity}, journal = {PHYSICAL REVIEW B}, volume = {91}, number = {12}, year = {2015}, month = {MAR 18}, issn = {1098-0121}, doi = {10.1103/PhysRevB.91.125127}, author = {Pixley, J. H. and Cai, Ang and Si, Qimiao} } @conference { ISI:000353892600004, title = {Coherent control of energy transfer in a quantum dot strongly coupled to a photonic crystal molecule}, booktitle = {ADVANCES IN PHOTONICS OF QUANTUM COMPUTING, MEMORY, AND COMMUNICATION VIII}, series = {Proceedings of SPIE}, volume = {9377}, year = {2015}, note = {Conference on Advances in Photonics of Quantum Computing, Memory, and Communication VIII, San Francisco, CA, FEB 10-12, 2015}, isbn = {978-1-62841-467-7}, issn = {0277-786X}, doi = {10.1117/12.2078199}, author = {Cai, Tao and Bose, Ranojoy and Choudhury, Kaushik Roy and Solomon, Glenn S. and Waks, Edo}, editor = {Hasan, ZU and Hemmer, PR and Lee, H and Migdall, AL} } @article { ISI:000356473300003, title = {Conductance spectroscopy of topological superconductor wire junctions}, journal = {PHYSICAL REVIEW B}, volume = {91}, number = {21}, year = {2015}, month = {JUN 18}, pages = {214513}, issn = {1098-0121}, doi = {10.1103/PhysRevB.91.214513}, author = {Setiawan, F. and Brydon, P. M. R. and Sau, Jay D. and S. Das Sarma} } @conference { ISI:000353892600001, title = {Control of the cavity reflectivity using a single quantum dot spin}, booktitle = {ADVANCES IN PHOTONICS OF QUANTUM COMPUTING, MEMORY, AND COMMUNICATION VIII}, series = {Proceedings of SPIE}, volume = {9377}, year = {2015}, note = {Conference on Advances in Photonics of Quantum Computing, Memory, and Communication VIII, San Francisco, CA, FEB 10-12, 2015}, isbn = {978-1-62841-467-7}, issn = {0277-786X}, doi = {10.1117/12.2079733}, author = {Sun, Shuo and Kim, Hyochul and Solomon, Glenn S. and Waks, Edo}, editor = {Hasan, ZU and Hemmer, PR and Lee, H and Migdall, AL} } @article { ISI:000350169700003, title = {Correlation effects in La, Ce, and lanthanide ions}, journal = {PHYSICAL REVIEW A}, volume = {91}, number = {2}, year = {2015}, month = {FEB 9}, pages = {022504}, issn = {1050-2947}, doi = {10.1103/PhysRevA.91.022504}, author = {Safronova, M. S. and Safronova, U. I. and Clark, Charles W.} } @article { ISI:000364024800001, title = {Dynamical Detection of Topological Phase Transitions in Short-Lived Atomic Systems}, journal = {PHYSICAL REVIEW LETTERS}, volume = {115}, number = {19}, year = {2015}, month = {NOV 4}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.115.190401}, author = {Setiawan, F. and Sengupta, K. and Ian B Spielman and Sau, Jay D.} } @article { ISI:000364471100001, title = {Effects of large induced superconducting gap on semiconductor Majorana nanowires}, journal = {PHYSICAL REVIEW B}, volume = {92}, number = {17}, year = {2015}, month = {NOV 12}, issn = {1098-0121}, doi = {10.1103/PhysRevB.92.174511}, author = {Cole, William S. and S. Das Sarma and Stanescu, Tudor D.} } @article { ISI:000366339600012, title = {Electronic Transport and Possible Superconductivity at Van Hove Singularities in Carbon Nanotubes}, journal = {NANO LETTERS}, volume = {15}, number = {12}, year = {2015}, month = {DEC}, pages = {7859-7866}, issn = {1530-6984}, doi = {10.1021/acs.nanolett.5b02564}, author = {Yang, Y. and Fedorov, G. and Shafranjuk, S. E. and Klapwijk, T. M. and Cooper, B. K. and Lewis, R. M. and Lobb, C. J. and Barbara, P.} } @article { ISI:000365002800001, title = {Emergence of Chaotic Scattering in Ultracold Er and Dy}, journal = {PHYSICAL REVIEW X}, volume = {5}, number = {4}, year = {2015}, month = {NOV 19}, issn = {2160-3308}, doi = {10.1103/PhysRevX.5.041029}, author = {Maier, T. and Kadau, H. and Schmitt, M. and Wenzel, M. and Ferrier-Barbut, I. and Pfau, T. and Frisch, A. and Baier, S. and Aikawa, K. and Chomaz, L. and Mark, M. J. and Ferlaino, F. and Makrides, C. and Tiesinga, E. and Petrov, A. and Kotochigova, S.} } @article { ISI:000354248200005, title = {Enhancement of superconductivity via periodic modulation in a three-dimensional model of cuprates}, journal = {PHYSICAL REVIEW B}, volume = {91}, number = {18}, year = {2015}, month = {MAY 8}, issn = {1098-0121}, doi = {10.1103/PhysRevB.91.184506}, author = {Raines, Zachary M. and Stanev, Valentin and Victor M Galitski} } @article { ISI:000355956800005, title = {Entanglement entropy near Kondo-destruction quantum critical points}, journal = {PHYSICAL REVIEW B}, volume = {91}, number = {24}, year = {2015}, month = {JUN 10}, issn = {1098-0121}, doi = {10.1103/PhysRevB.91.245122}, author = {Pixley, J. H. and Chowdhury, Tathagata and Miecnikowski, M. T. and Stephens, Jaimie and Wagner, Christopher and Ingersent, Kevin} } @article { ISI:000358373600004, title = {Equivalence of topological mirror superconductivity and chiral superconductivity in one dimension}, journal = {PHYSICAL REVIEW B}, volume = {92}, number = {4}, year = {2015}, month = {JUL 22}, issn = {1098-0121}, doi = {10.1103/PhysRevB.92.045421}, author = {Dumitrescu, Eugene and Sharma, Girish and Sau, Jay D. and Tewari, Sumanta} } @article { ISI:000367065800003, title = {Excitonic and nematic instabilities on the surface of topological Kondo insulators}, journal = {PHYSICAL REVIEW B}, volume = {92}, number = {24}, year = {2015}, month = {DEC 21}, issn = {1098-0121}, doi = {10.1103/PhysRevB.92.245431}, author = {Roy, Bitan and Hofmann, Johannes and Stanev, Valentin and Sau, Jay D. and Galitski, Victor} } @article { ISI:000362342200001, title = {Extracting transition rates from zero-polarizability spectroscopy}, journal = {PHYSICAL REVIEW A}, volume = {92}, number = {4}, year = {2015}, month = {OCT 6}, pages = {040501}, issn = {1050-2947}, doi = {10.1103/PhysRevA.92.040501}, author = {Safronova, M. S. and Zuhrianda, Z. and Safronova, U. I. and Clark, Charles W.} } @article {ISI:000372360400001, title = {Feshbach enhanced s-wave scattering of fermions: direct observation with optimized absorption imaging}, journal = {NEW JOURNAL OF PHYSICS}, volume = {18}, year = {2015}, month = {DEC 17}, pages = {013001}, issn = {1367-2630}, doi = {10.1088/1367-2630/18/1/013001}, author = {Genkina, D. and Aycock, L. M. and Stuhl, B. K. and Lu, H-I and Williams, R. A. and Ian B Spielman} } @article { ISI:000351634800008, title = {From membrane-in-the-middle to mirror-in-the-middle with a high-reflectivity sub-wavelength grating}, journal = {ANNALEN DER PHYSIK}, volume = {527}, number = {1-2, SI}, year = {2015}, month = {JAN}, pages = {81-88}, issn = {0003-3804}, doi = {10.1002/andp.201400142}, author = {Stambaugh, Corey and Xu, Haitan and Kemiktarak, Utku and Taylor, Jacob and Lawall, John} } @article { ISI:000358928600002, title = {Gauge matters: observing the vortex-nucleation transition in a Bose condensate}, journal = {NEW JOURNAL OF PHYSICS}, volume = {17}, year = {2015}, month = {JUN 18}, pages = {065016}, issn = {1367-2630}, doi = {10.1088/1367-2630/17/6/065016}, author = {LeBlanc, L. J. and Jimenez-Garcia, K. and Williams, R. A. and Beeler, M. C. and Phillips, W. D. and Ian B Spielman} } @article { ISI:000360894300012, title = {Gigantic Surface Lifetime of an Intrinsic Topological Insulator}, journal = {PHYSICAL REVIEW LETTERS}, volume = {115}, number = {11}, year = {2015}, month = {SEP 9}, pages = {116801}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.115.116801}, author = {Neupane, Madhab and Xu, Su-Yang and Ishida, Yukiaki and Jia, Shuang and Fregoso, Benjamin M. and Liu, Chang and Belopolski, Ilya and Bian, Guang and Alidoust, Nasser and Durakiewicz, Tomasz and Victor M Galitski and Shin, Shik and Cava, Robert J. and Hasan, M. Zahid} } @article { ISI:000358737200017, title = {Harnessing high-dimensional hyperentanglement through a biphoton frequency comb}, journal = {NATURE PHOTONICS}, volume = {9}, number = {8}, year = {2015}, month = {AUG}, pages = {536+}, issn = {1749-4885}, doi = {10.1038/NPHOTON.2015.110}, author = {Xie, Zhenda and Zhong, Tian and Shrestha, Sajan and Xu, XinAn and Liang, Junlin and Gong, Yan-Xiao and Bienfang, Joshua C. and Restelli, Alessandro and Shapiro, Jeffrey H. and Wong, Franco N. C. and Wong, Chee Wei} } @article { ISI:000348759300001, title = {Helical spin texture of surface states in topological superconductors}, journal = {NEW JOURNAL OF PHYSICS}, volume = {17}, year = {2015}, month = {JAN 15}, issn = {1367-2630}, doi = {10.1088/1367-2630/17/1/013016}, author = {Brydon, P. M. R. and Schnyder, Andreas P. and Timm, Carsten} } @article { ISI:000365507200003, title = {Hybridization of Higgs modes in a bond-density-wave state in cuprates}, journal = {PHYSICAL REVIEW B}, volume = {92}, number = {18}, year = {2015}, month = {NOV 24}, issn = {1098-0121}, doi = {10.1103/PhysRevB.92.184511}, author = {Raines, Zachary M. and Stanev, Valentin G. and Galitski, Victor M.} } @article {3000, title = {Hyperfine Anomalies in Fr: Boundaries of the Spherical Single Particle Model}, journal = {Phys. Rev. Lett.}, volume = {115}, year = {2015}, month = {Jul}, pages = {042501}, doi = {10.1103/PhysRevLett.115.042501}, url = {http://link.aps.org/doi/10.1103/PhysRevLett.115.042501}, author = {Zhang, J. and Tandecki, M. and Collister, R. and Aubin, S. and Behr, J. A. and Gomez, E. and Gwinner, G. and Orozco, L. A. and Pearson, M. R. and Sprouse, G. D.} } @article { ISI:000364011400010, title = {Injection locking of a semiconductor double-quantum-dot micromaser}, journal = {PHYSICAL REVIEW A}, volume = {92}, number = {5}, year = {2015}, month = {NOV 2}, issn = {1050-2947}, doi = {10.1103/PhysRevA.92.053802}, author = {Liu, Y. -Y. and Stehlik, J. and Gullans, M. J. and Taylor, J. M. and Petta, J. R.} } @article { ISI:000352864800008, title = {Laser acceleration of protons using multi-ion plasma gaseous targets}, journal = {NEW JOURNAL OF PHYSICS}, volume = {17}, year = {2015}, month = {FEB 4}, issn = {1367-2630}, doi = {10.1088/1367-2630/17/2/023018}, author = {Liu, Tung-Chang and Shao, Xi and Liu, Chuan-Sheng and Eliasson, Bengt and Hill, III, W. T. and Wang, Jyhpyng and Chen, Shih-Hung} } @article { ISI:000352196000006, title = {Long range p-wave proximity effect into a disordered metal}, journal = {PHYSICAL REVIEW B}, volume = {91}, number = {9}, year = {2015}, month = {MAR 30}, issn = {1098-0121}, doi = {10.1103/PhysRevB.91.094518}, author = {Keser, Aydin Cem and Stanev, Valentin and Victor M Galitski} } @article {2899, title = {Magic wavelengths for the 5s-18s transition in rubidium}, journal = {Phys. Rev. A}, volume = {91}, year = {2015}, month = {Mar}, pages = {032518}, doi = {10.1103/PhysRevA.91.032518}, url = {http://link.aps.org/doi/10.1103/PhysRevA.91.032518}, author = {Goldschmidt, E A and Norris, D G and Koller, S B and Wyllie, R and Brown, R C and Porto, J V and Safronova, U I and Safronova, M S} } @article { ISI:000361665700003, title = {Magnetic catalysis and axionic charge density wave in Weyl semimetals}, journal = {PHYSICAL REVIEW B}, volume = {92}, number = {12}, year = {2015}, month = {SEP 22}, issn = {1098-0121}, doi = {10.1103/PhysRevB.92.125141}, author = {Roy, Bitan and Sau, Jay D.} } @article {ISI:000351341100004, title = {Majorana fermions in chiral topological ferromagnetic nanowires}, journal = {PHYSICAL REVIEW B}, volume = {91}, number = {9}, year = {2015}, month = {MAR 12}, pages = {094505}, issn = {1098-0121}, doi = {10.1103/PhysRevB.91.094505}, author = {Dumitrescu, Eugene and Roberts, Brenden and Tewari, Sumanta and Sau, Jay D. and S. Das Sarma} } @article {ISI:000350480100001, title = {Majorana fermions in ferromagnetic chains on the surface of bulk spin-orbit coupled s-wave superconductors}, journal = {SCIENTIFIC REPORTS}, volume = {5}, year = {2015}, month = {MAR 6}, pages = {8880}, issn = {2045-2322}, doi = {10.1038/srep08880}, author = {Hui, Hoi-Yin and Brydon, P. M. R. and Sau, Jay D. and Tewari, S. and S. Das Sarma} } @conference { ISI:000354263300010, title = {Measuring the Propagation of Information and Entanglement in Dispersive Media}, booktitle = {SLOW LIGHT, FAST LIGHT, AND OPTO-ATOMIC PRECISION METROLOGY VIII}, series = {Proceedings of SPIE}, volume = {9378}, year = {2015}, note = {Conference on Slow Light, Fast Light, and Opto-Atomic Precision Metrology VIII, San Francisco, CA, FEB 08-12, 2015}, isbn = {978-1-62841-468-4}, issn = {0277-786X}, doi = {10.1117/12.2086776}, author = {Clark, Jeremy B. and Glasser, Ryan T. and Glorieux, Quentin and Vogl, Ulrich and Li, Tian and Jones, Kevin M. and Lett, Paul D.}, editor = {Shahriar, SM and Scheuer, J} } @article { ISI:000348775000038, title = {Michelson-Morley analogue for electrons using trapped ions to test Lorentz symmetry}, journal = {NATURE}, volume = {517}, number = {7536}, year = {2015}, month = {JAN 29}, pages = {592-U357}, issn = {0028-0836}, doi = {10.1038/nature14091}, author = {Pruttivarasin, T. and Ramm, M. and Porsev, S. G. and Tupitsyn, I. I. and Safronova, M. S. and Hohensee, M. A. and Haeffner, H.} } @article { ISI:000360284100012, title = {Mirror-field entanglement in a microscopic model for quantum optomechanics}, journal = {PHYSICAL REVIEW A}, volume = {92}, number = {2}, year = {2015}, month = {AUG 28}, pages = {023852}, issn = {1050-2947}, doi = {10.1103/PhysRevA.92.023852}, author = {Sinha, Kanupriya and Lin, Shih-Yuin and Hu, B. L.} } @article {ISI:000351362200012, title = {Movable Thin-Film Superconducting Resonator Coupled to a Tapered Optical Microfiber at 15 mK}, journal = {IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY}, volume = {25}, number = {3}, year = {2015}, month = {JUN}, pages = {1700305}, issn = {1051-8223}, doi = {10.1109/TASC.2014.2379628}, author = {Voigt, K. D. and Hertzberg, J. B. and Hoffman, J. E. and Grover, J. A. and Solano, P. and Budoyo, R. P. and Ballard, C. and Lee, J. and Anderson, J. R. and Lobb, C. J. and Orozco, L. A. and Rolston, S. L. and Wellstood, E. C.} } @article {2743, title = {Nanoscale probing of image dipole interactions in a metallic nanostructure}, journal = {Nature Communications}, volume = {6}, year = {2015}, pages = {6558}, doi = {10.1038/ncomms7558}, url = {http://www.nature.com/ncomms/2015/150319/ncomms7558/full/ncomms7558.html}, author = {Ropp, Chad and Cummins, Zachary and Nah, Sanghee and John T Fourkas and Shapiro, Benjamin and Waks, Edo} } @article { ISI:000365771800007, title = {Nonlinear microwave photon occupancy of a driven resonator strongly coupled to a transmon qubit}, journal = {PHYSICAL REVIEW A}, volume = {92}, number = {6}, year = {2015}, month = {DEC 2}, issn = {1050-2947}, doi = {10.1103/PhysRevA.92.063801}, author = {Suri, B. and Keane, Z. K. and Bishop, Lev S. and Novikov, S. and Wellstood, F. C. and Palmer, B. 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E. and Sinha, K. and Taylor, J. M. and Kimble, H. J.} } @article { ISI:000338995700025, title = {Ultrahigh transmission optical nanofibers}, journal = {AIP ADVANCES}, volume = {4}, number = {6}, year = {2014}, month = {JUN}, issn = {2158-3226}, doi = {10.1063/1.4879799}, author = {Hoffman, J. E. and Ravets, S. and Grover, J. A. and Solano, P. and Kordell, P. R. and Wong-Campos, J. D. and Orozco, L. A. and Rolston, S. L.} } @article { ISI:000332518100093, title = {Ultra-sensitive chip-based photonic temperature sensor using ring resonator structures}, journal = {OPTICS EXPRESS}, volume = {22}, number = {3}, year = {2014}, month = {FEB 10}, pages = {3098-3104}, issn = {1094-4087}, doi = {10.1364/OE.22.003098}, author = {Xu, Haitan and Mohammad Hafezi and Jingyun Fan and Jacob M Taylor and G F Strouse and Ahmed, Zeeshan} } @article { ISI:000319294100058, title = {Asymmetric superconducting quantum interference devices for suppression of phase diffusion in small Josephson junctions}, journal = {J. Appl. Phys.}, volume = {113}, number = {18}, year = {2013}, month = {MAY 14}, pages = {183905}, issn = {0021-8979}, doi = {10.1063/1.4804057}, author = {D F Sullivan and S K Dutta and M Dreyer and M A Gubrud and A Roychowdhury and Jeffrey R Anderson and Christopher J Lobb and F C Wellstood} } @article { ISI:000322777000002, title = {Autler-Townes splitting in a three-dimensional transmon superconducting qubit}, journal = {Phys. Rev. B}, volume = {88}, number = {6}, year = {2013}, month = {AUG 2}, issn = {1098-0121}, doi = {10.1103/PhysRevB.88.060503}, author = {S Novikov and J E Robinson and Z K Keane and B Suri and F C Wellstood and B S Palmer} } @article {ISI:000313939000002, title = {Blackbody-radiation shift in the Sr optical atomic clock}, journal = {Phys. Rev. A}, volume = {87}, number = {1}, year = {2013}, month = {jan}, pages = {012509}, abstract = {We evaluated the static and dynamic polarizabilities of the 5s(2) S-1(0) and 5s5p P-3(0)0 states of Sr using the high-precision relativistic configuration interaction combined with the all-order method. Our calculation explains the discrepancy between the recent experimental 5s(2) S-1(0) - 5s5p P-3(0)0 dc Stark shift measurement Delta alpha = 247.379(7) \{[\}Middelmann et al., Phys. Rev. Lett. 109, 263004 (2012)] and the earlier theoretical result of 261(4) a.u. \{[\} Porsev and Derevianko, Phys. Rev. A 74, 020502(R) (2006)]. Our present value of 247.5 a.u. is in excellent agreement with the experimental result. We also evaluated the dynamic correction to the BBR shift with 1\% uncertainty; -0.1492(16) Hz. The dynamic correction to the BBR shift is unusually large in the case of Sr (7\%) and it enters significantly into the uncertainty budget of the Sr optical lattice clock. We suggest future experiments that could further reduce the present uncertainties. DOI: 10.1103/PhysRevA.87.012509

}, issn = {1050-2947}, doi = {10.1103/PhysRevA.87.012509}, author = {Marianna S Safronova and S G Porsev and U I Safronova and Mikhail G Kozlov and Charles W Clark} } @article { ISI:000313030700004, title = {Coherent nonlocal transport in quantum wires with strongly coupled electrodes}, journal = {Phys. Rev. B}, volume = {87}, number = {4}, year = {2013}, month = {JAN 3}, issn = {1098-0121}, doi = {10.1103/PhysRevB.87.045403}, author = {Y Yang and G Fedorov and P Barbara and S E Shafranjuk and Benjamin K Cooper and R M Lewis and Christopher J Lobb} } @article { ISI:000313408200001, title = {Control of conditional quantum beats in cavity QED: amplitude decoherence and phase shifts}, journal = {New J. Phys.}, volume = {15}, year = {2013}, month = {01/2013}, pages = {013017}, issn = {1367-2630}, doi = {10.1088/1367-2630/15/1/013017}, author = {A D Cimmarusti and C A Schroeder and B D Patterson and Luis A Orozco and P Barberis-Blostein and Howard J Carmichael} } @article {ISI:000318268800018, title = {Controlled coupling of photonic crystal cavities using photochromic tuning}, journal = {Appl. Phys. Lett.}, volume = {102}, number = {14}, year = {2013}, pages = {141118}, issn = {0003-6951}, doi = {10.1063/1.4802238}, author = {Cai, Tao and Ranojoy Bose and Glenn S Solomon and Edo Waks} } @article { ISI:000317823800008, title = {Controlling the spatial location of photoexcited electrons in semiconductor CdSe/CdS core/shell nanorods}, journal = {Phys. Rev. B}, volume = {87}, number = {15}, year = {2013}, month = {APR 22}, issn = {1098-0121}, doi = {10.1103/PhysRevB.87.155427}, author = {She, Chunxing and Garnett W Bryant and Demortiere, Arnaud and Shevchenko, Elena V. and Matthew Pelton} } @article { ISI:000315726900002, title = {Critically evaluated theoretical atomic properties of Y III}, journal = {PHYSICAL REVIEW A}, volume = {87}, number = {3}, year = {2013}, month = {MAR 5}, issn = {1050-2947}, doi = {10.1103/PhysRevA.87.032501}, author = {Safronova, U. I. and Safronova, M. S.} } @inbook { ISI:000335188500012, title = {Cumulant Dynamics of Strongly Interacting Ultracold Gases}, booktitle = {QUANTUM GASES: FINITE TEMPERATURE AND NON-EQUILIBRIUM DYNAMICS}, series = {Cold Atoms}, volume = {1}, year = {2013}, pages = {121-131}, isbn = {978-1-848168-12-1; 978-1-848168-10-7}, issn = {2045-9734}, author = {Hanna, Thomas M. and Mur-Petit, Jordi}, editor = {Proukakis, N and Gardiner, S and Davis, M and Szymanska, M} } @article { ISI:000324386900059, title = {Decoherence in a pair of long-lived Cooper-pair boxes}, journal = {J. Appl. Phys.}, volume = {114}, number = {9}, year = {2013}, month = {SEP 7}, issn = {0021-8979}, doi = {10.1063/1.4820260}, author = {Zaretskey, V. and S Novikov and B Suri and Kim, Z. and F C Wellstood and B S Palmer} } @article { ISI:000318488000013, title = {Demonstration of a dynamic bandpass frequency filter in a rare-earth ion-doped crystal}, journal = {JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS}, volume = {30}, number = {5}, year = {2013}, month = {MAY}, pages = {1173-1177}, issn = {0740-3224}, doi = {10.1364/JOSAB.30.001173}, author = {Beavan, Sarah E. and Goldschmidt, Elizabeth A. and Sellars, Matthew J.} } @article { ISI:000323032300006, title = {Density of states of disordered topological superconductor-semiconductor hybrid nanowires}, journal = {Phys. Rev. B}, volume = {88}, number = {6}, year = {2013}, month = {AUG 12}, pages = {064506}, issn = {1098-0121}, doi = {10.1103/PhysRevB.88.064506}, author = {Jay D Sau and S. Das Sarma} } @article { ISI:000329497800010, title = {Detection of topological matter with quantum gases}, journal = {ANNALEN DER PHYSIK}, volume = {525}, number = {10-11, SI}, year = {2013}, month = {NOV}, pages = {797-807}, issn = {0003-3804}, doi = {10.1002/andp.201300110}, author = {Ian B Spielman} } @article {ISI:000316685100018, title = {Deterministic Photon Pairs and Coherent Optical Control of a Single Quantum Dot}, journal = {Phys. Rev. Lett.}, volume = {110}, number = {13}, year = {2013}, pages = {135505}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.110.135505}, author = {Jayakumar, Harishankar and Predojevic, Ana and Huber, Tobias and Kauten, Thomas and Glenn S Solomon and Weihs, Gregor} } @article { ISI:000316661200003, title = {Dimensional crossover in spin-orbit-coupled semiconductor nanowires with induced superconducting pairing}, journal = {Phys. Rev. B}, volume = {87}, number = {9}, year = {2013}, month = {MAR 22}, pages = {094518}, issn = {1098-0121}, doi = {10.1103/PhysRevB.87.094518}, author = {Tudor D Stanescu and Roman M Lutchyn and S. Das Sarma} } @article {ISI:000318677300039, title = {Direct imaging of topological edge states in cold-atom systems}, journal = {PNAS}, volume = {110}, number = {17}, year = {2013}, month = {apr}, pages = {6736}, keywords = {chiral edge states, degenerate atomic gases, optical lattices, Quantum Hall effects}, issn = {0027-8424}, doi = {10.1073/pnas.1300170110}, author = {Nathan Goldman and Dalibard, Jean and Dauphin, Alexandre and Fabrice Gerbier and Maciej Lewenstein and Peter Zoller and Ian B Spielman} } @article {ISI:000321293200001, title = {Direct observation of zitterbewegung in a Bose-Einstein condensate}, journal = {New J. Phys.}, volume = {15}, year = {2013}, month = {jul}, pages = {073011}, issn = {1367-2630}, doi = {10.1088/1367-2630/15/7/073011}, author = {Lindsay J LeBlanc and Matthew C Beeler and Karina Jim{\'e}nez-Garc{\'\i}a and Abigail R Perry and Seiji Sugawa and Ross A Williams and Ian B Spielman} } @conference { ISI:000355262503349, title = {Efficient, low-noise, single-photon frequency conversion}, booktitle = {2013 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO)}, series = {Conference on Lasers and Electro-Optics}, year = {2013}, note = {Conference on Lasers and Electro-Optics (CLEO), San Jose, CA, JUN 09-14, 2013}, isbn = {978-1-55752-973-2}, issn = {2160-9020}, author = {Kuo, Paulina S. and Pelc, Jason S. and Slattery, Oliver and Kim, Yong-Su and Fejer, M. M. and Tang, Xiao} } @article {1943, title = {Electrically Protected Resonant Exchange Qubits in Triple Quantum Dots}, journal = {Phys. Rev. Lett.}, volume = {111}, year = {2013}, month = {Jul}, pages = {050502}, doi = {10.1103/PhysRevLett.111.050502}, url = {http://link.aps.org/doi/10.1103/PhysRevLett.111.050502}, author = {Jacob M Taylor and V Srinivasa and J Medford} } @article {1876, title = {Emergence and Frustration of Magnetism with Variable-Range Interactions in a Quantum Simulator}, journal = {Science}, volume = {340}, year = {2013}, pages = {583}, keywords = {Multiple JQI Affil., Single Fellow}, url = {http://www.sciencemag.org/content/340/6132/583}, author = {Rajibul Islam and Crystal Senko and W C Campbell and Simcha Korenblit and J Smith and A Lee and Emily E Edwards and C C J Wang and J K Freericks and Christopher Monroe} } @article {2321, title = {Enhanced spin-triplet superconductivity near dislocations in Sr2RuO4}, journal = {Nature Communications}, volume = {4}, year = {2013}, month = {11/2013}, pages = {2596}, abstract = {Superconductors with a chiral p-wave pairing are of great interest because they could support Majorana modes that could enable the development of topological quantum computing technologies that are robust against decoherence. Sr2RuO4 is widely believed to be a chiral p-wave superconductor. Yet, the mechanism by which superconductivity emerges in this, and indeed most other unconventional superconductors, remains unclear. Here we show that the local superconducting transition temperature in the vicinity of lattice dislocations in Sr2RuO4 can be up to twice that of its bulk. This is all the more surprising for the fact that disorder is known to easily quench superconductivity in this material. With the help of a phenomenological theory that takes into account the crystalline symmetry near a dislocation and the pairing symmetry of Sr2RuO4, we predict that a similar enhancement should emerge as a consequence of symmetry reduction in any superconductor with a two-component order parameter.

}, doi = {10.1038/ncomms3596 }, url = {http://www.nature.com/ncomms/2013/131108/ncomms3596/full/ncomms3596.html?WT.ec_id=NCOMMS-20131113}, author = {Y A Ying and N E Staley and Y Xin and Kai Sun and X Cai and D Fobes and T J Liu and Z Q Mao and Y Liu} } @article { ISI:000326148700059, title = {Evidence for hydrogen two-level systems in atomic layer deposition oxides}, journal = {APPLIED PHYSICS LETTERS}, volume = {103}, number = {16}, year = {2013}, month = {OCT 14}, issn = {0003-6951}, doi = {10.1063/1.4826253}, author = {Khalil, M. S. and Stoutimore, M. J. A. and Gladchenko, S. and Holder, A. M. and Musgrave, C. B. and Kozen, A. C. and Rubloff, G. and Liu, Y. Q. and Gordon, R. G. and Yum, J. H. and Banerjee, S. K. and Lobb, C. J. and Osborn, K. D.} } @article { ISI:000324630600001, title = {Exactly soluble lattice models for non-Abelian states of matter in two dimensions}, journal = {PHYSICAL REVIEW B}, volume = {88}, number = {11}, year = {2013}, month = {SEP 19}, issn = {1098-0121}, doi = {10.1103/PhysRevB.88.115133}, author = {Koch-Janusz, Maciej and Levin, Michael and Stern, Ady} } @article { ISI:000318553000068, title = {Examining the role of hydrogen in the electrical performance of in situ fabricated metal-insulator-metal trilayers using an atomic layer deposited Al2O3 dielectric}, journal = {Appl. Phys. Lett.}, volume = {102}, number = {17}, year = {2013}, month = {APR 29}, issn = {0003-6951}, doi = {10.1063/1.4801979}, author = {Kozen, Alexander C. and Schroeder, Marshall A. and Osborn, Kevin D. and Christopher J Lobb and Rubloff, Gary W.} } @article { ISI:000322674700003, title = {Experimental performance of a quantum simulator: Optimizing adiabatic evolution and identifying many-body ground states}, journal = {Phys. Rev. A}, volume = {88}, number = {1}, year = {2013}, month = {JUL 31}, pages = {012334}, issn = {1050-2947}, doi = {10.1103/PhysRevA.88.012334}, author = {Phil Richerme and Crystal Senko and J Smith and A Lee and Simcha Korenblit and Christopher Monroe} } @conference { ISI:000355316301398, title = {Experimental test of the robustness of the non-classicality of single photons}, booktitle = {2013 CONFERENCE ON AND INTERNATIONAL QUANTUM ELECTRONICS CONFERENCE LASERS AND ELECTRO-OPTICS EUROPE (CLEO EUROPE/IQEC)}, year = {2013}, note = {Conference on Lasers and Electro-Optics Europe \& International Quantum Electronics Conference (CLEO/Europe-IQEC), Munich, GERMANY, MAY 12-16, 2013}, isbn = {978-1-4799-0594-2}, author = {Huber, Tobias and Predojevic, Ana and Jezek, Miroslav and Foeger, Daniel and Solomon, Glenn S. and Filip, Radim and Weihs, Gregor} } @article { ISI:000323241000077, title = {Fabrication of Nanoassemblies Using Flow Control}, journal = {Nano Lett.}, volume = {13}, number = {8}, year = {2013}, month = {AUG}, pages = {3936}, issn = {1530-6984}, doi = {10.1021/nl402059u}, author = {Ropp, Chad and Cummins, Zachary and Nah, Sanghee and Qin, Sijia and Seog, Ji Hyun and Lee, Sang Bok and John T Fourkas and Shapiro, Benjamin and Edo Waks} } @conference { ISI:000326980500015, title = {Feedback in a cavity QED system for control of quantum beats}, booktitle = {ICAP 2012 - 23RD INTERNATIONAL CONFERENCE ON ATOMIC PHYSICS}, series = {EPJ Web of Conferences}, volume = {57}, year = {2013}, note = {23rd International Conference on Atomic Physics (ICAP), Ecole Polytechnique, FRANCE, JUL 23-27, 2012}, issn = {2100-014X}, doi = {10.1051/epjconf/20135703005}, author = {Cimmarusti, A. D. and Patterson, B. D. and Schroeder, C. A. and Orozco, L. A. and Barberis-Blostein, P. and Carmichael, H. J.}, editor = {Dulieu, O and Grangier, P and Leduc, M and Perrin, H} } @article { ISI:000323481000003, title = {Gradient echo memory in an ultra-high optical depth cold atomic ensemble}, journal = {NEW JOURNAL OF PHYSICS}, volume = {15}, year = {2013}, month = {AUG 23}, issn = {1367-2630}, doi = {10.1088/1367-2630/15/8/085027}, author = {Sparkes, B. M. and Bernu, J. and Hosseini, M. and Geng, J. and Glorieux, Q. and Altin, P. A. and Lam, P. K. and Robins, N. P. and Buchler, B. C.} } @article {ISI:000320622600014, title = {Heterodyne measurement of resonant elastic scattering from epitaxial quantum dots}, journal = {Appl. Phys. Lett.}, volume = {102}, number = {23}, year = {2013}, pages = {231114}, issn = {0003-6951}, doi = {10.1063/1.4809594}, author = {Michael Metcalfe and Glenn S Solomon and John R Lawall} } @conference { ISI:000326703000013, title = {A hybrid quantum system of atoms trapped on ultrathin optical fibers coupled to superconductors}, booktitle = {QUANTUM COMMUNICATIONS AND QUANTUM IMAGING XI}, series = {Proceedings of SPIE}, volume = {8875}, year = {2013}, note = {Conference on Quantum Communications and Quantum Imaging XI, San Diego, CA, AUG 26-29, 2013}, isbn = {978-0-8194-9725-3}, issn = {0277-786X}, doi = {10.1117/12.2024362}, author = {Rolston, S. L. and Anderson, J. R. and Chukwu, U. and Grover, J. and Hertzberg, J. B. and Hoffman, J. E. and Kordell, P. and Lee, J. and Lobb, C. J. and Orozco, L. A. and Ravets, S. and Solano, P. and Voigt, K. D. and Wellstood, F. C. and Wong-Campos, J. D. and Beadie, G. and Fatemi, F. K.}, editor = {Meyers, RE and Shih, Y and Deacon, KS} } @article { ISI:000327237700003, title = {Individual addressing in quantum computation through spatial refocusing}, journal = {PHYSICAL REVIEW A}, volume = {88}, number = {5}, year = {2013}, month = {NOV 21}, issn = {1050-2947}, doi = {10.1103/PhysRevA.88.052325}, author = {Shen, C. and Gong, Z-X and Duan, L-M} } @article { ISI:000313951300014, title = {Integer Quantum Hall Effect for Bosons}, journal = {PHYSICAL REVIEW LETTERS}, volume = {110}, number = {4}, year = {2013}, month = {JAN 22}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.110.046801}, author = {Senthil, T. and Levin, Michael} } @inbook { ISI:000335188500007, title = {Introduction to Theoretical Modelling}, booktitle = {QUANTUM GASES: FINITE TEMPERATURE AND NON-EQUILIBRIUM DYNAMICS}, series = {Cold Atoms}, volume = {1}, year = {2013}, pages = {63-83}, isbn = {978-1-848168-12-1; 978-1-848168-10-7}, issn = {2045-9734}, author = {Davis, Matthew J. and Gardiner, Simon A. and Hanna, Thomas M. and Nicolai Nygaard and Proukakis, Nick P. and Szymanska, Marzena H.}, editor = {Proukakis, N and Gardiner, S and Davis, M and Szymanska, M} } @inbook { ISI:000319020500005, title = {LIGHT INDUCED GAUGE FIELDS FOR ULTRACOLD NEUTRAL ATOMS}, booktitle = {ANNUAL REVIEW OF COLD ATOMS AND MOLECULES, VOL 1}, series = {Annual Review of Cold Atoms and Molecules}, volume = {1}, year = {2013}, pages = {145-187}, isbn = {978-981-4440-39-4}, issn = {2315-4926}, author = {Ian B Spielman}, editor = {Madison, KW and Wang, YQ and Rey, AM and Bongs, K} } @article { ISI:000324827200059, title = {Linear and nonlinear coupling between transverse modes of a nanomechanical resonator}, journal = {JOURNAL OF APPLIED PHYSICS}, volume = {114}, number = {11}, year = {2013}, month = {SEP 21}, issn = {0021-8979}, doi = {10.1063/1.4821273}, author = {Truitt, P. A. and Hertzberg, J. B. and Altunkaya, E. and Schwab, K. C.} } @article {ISI:000318471400008, title = {Magic wavelengths for optical cooling and trapping of potassium}, journal = {Phys. Rev. A}, volume = {87}, number = {5}, year = {2013}, month = {may}, pages = {052504}, issn = {1050-2947}, doi = {10.1103/PhysRevA.87.052504}, author = {Marianna S Safronova and U I Safronova and Charles W Clark} } @article { ISI:000332103500001, title = {Magnetic dipole and electric quadrupole moments of the Th-229 nucleus}, journal = {PHYSICAL REVIEW A}, volume = {88}, number = {6}, year = {2013}, month = {DEC 26}, issn = {1050-2947}, doi = {10.1103/PhysRevA.88.060501}, author = {Safronova, M. S. and Safronova, U. I. and Radnaev, A. G. and Campbell, C. J. and A. Kuzmich} } @article { ISI:000317190800014, title = {Magnetic Flux Noise in dc SQUIDs: Temperature and Geometry Dependence}, journal = {Phys. Rev. Lett.}, volume = {110}, number = {14}, year = {2013}, month = {APR 5}, pages = {147002}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.110.147002}, author = {S M Anton and J S Birenbaum and S R O{\textquoteright}Kelley and V Bolkhovsky and D A Braje and G Fitch and M Neeley and G C Hilton and H M Cho and K D Irwin and F C Wellstood and Oliver, W. D. and A Shnirman and Clarke, John} } @article { ISI:000324542900008, title = {Magnetically Generated Spin-Orbit Coupling for Ultracold Atoms}, journal = {Phys. Rev. Lett.}, volume = {111}, number = {12}, year = {2013}, month = {SEP 18}, pages = {125301}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.111.125301}, author = {Brandon M Anderson and Ian B Spielman and Gediminas Juzeliunas} } @article {ISI:000318151600065, title = {Measurement and modification of biexciton-exciton time correlations}, journal = {Optics Express}, volume = {21}, number = {8}, year = {2013}, month = {apr}, pages = {9890}, issn = {1094-4087}, doi = {10.1364/OE.21.009890}, author = {Huber, Tobias and Predojevic, Ana and Zoubi, Hashem and Jayakumar, Harishankar and Glenn S Solomon and Weihs, Gregor} } @article {ISI:000313427300004, title = {Measuring topology in a laser-coupled honeycomb lattice: from Chern insulators to topological semi-metals}, journal = {New J. Phys.}, volume = {15}, year = {2013}, pages = {013025}, abstract = {Ultracold fermions trapped in a honeycomb optical lattice constitute a versatile setup to experimentally realize the Haldane model (1988 Phys. Rev. Lett. 61 2015). In this system, a non-uniform synthetic magnetic flux can be engineered through laser-induced methods, explicitly breaking time-reversal symmetry. This potentially opens a bulk gap in the energy spectrum, which is associated with a non-trivial topological order, i.e. a non-zero Chern number. In this paper, we consider the possibility of producing and identifying such a robust Chern insulator in the laser-coupled honeycomb lattice. We explore a large parameter space spanned by experimentally controllable parameters and obtain a variety of phase diagrams, clearly identifying the accessible topologically non-trivial regimes. We discuss the signatures of Chern insulators in cold-atom systems, considering available detection methods. We also highlight the existence of topological semi-metals in this system, which are gapless phases characterized by non-zero winding numbers, not present in Haldane{\textquoteright}s original model.

}, issn = {1367-2630}, doi = {10.1088/1367-2630/15/1/013025}, author = {Nathan Goldman and E Anisimovas and Fabrice Gerbier and P Oehberg and Ian B Spielman and Gediminas Juzeliunas} } @article { ISI:000325502400003, title = {Mechanism for controlling the exciton fine structure in quantum dots using electric fields: Manipulation of exciton orientation and exchange splitting at the atomic scale}, journal = {Phys. Rev. B}, volume = {88}, number = {16}, year = {2013}, month = {OCT 7}, issn = {1098-0121}, doi = {10.1103/PhysRevB.88.161301}, author = {Garnett W Bryant and Natalia Malkova and Sims, James} } @article { ISI:000326118400002, title = {Microcanonical work and fluctuation relations for an open system: An exactly solvable model}, journal = {PHYSICAL REVIEW E}, volume = {88}, number = {4}, year = {2013}, month = {OCT 24}, issn = {1539-3755}, doi = {10.1103/PhysRevE.88.042136}, author = {Subasi, Y. and Jarzynski, C.} } @article {ISI:000316616400023, title = {Nanoscale imaging and spontaneous emission control with a single nano-positioned quantum dot}, journal = {Nat. Comm.}, volume = {4}, year = {2013}, month = {feb}, pages = {1447}, issn = {2041-1723}, doi = {10.1038/ncomms2477}, author = {Ropp, Chad and Cummins, Zachary and Nah, Sanghee and John T Fourkas and Shapiro, Benjamin and Edo Waks} } @article { ISI:000329437000003, title = {Observation of Autler-Townes effect in a dispersively dressed Jaynes-Cummings system}, journal = {NEW JOURNAL OF PHYSICS}, volume = {15}, year = {2013}, month = {DEC 5}, issn = {1367-2630}, doi = {10.1088/1367-2630/15/12/125007}, author = {B Suri and Z K Keane and Ruskov, R. and Bishop, Lev S. and Tahan, C. and S Novikov and J E Robinson and F C Wellstood and B S Palmer} } @conference { ISI:000355316300624, title = {Optical Readout of Coupling Between a Nanomembrane and an LC Circuit at Room Temperature}, booktitle = {2013 CONFERENCE ON AND INTERNATIONAL QUANTUM ELECTRONICS CONFERENCE LASERS AND ELECTRO-OPTICS EUROPE (CLEO EUROPE/IQEC)}, year = {2013}, note = {Conference on Lasers and Electro-Optics Europe \& International Quantum Electronics Conference (CLEO/Europe-IQEC), Munich, GERMANY, MAY 12-16, 2013}, isbn = {978-1-4799-0594-2}, author = {Bagci, T. and Simonsen, A. and Zeuthen, E. and Taylor, J. M. and Villanueva, L. G. and Schmid, S. and Sorensen, A. and Schliesser, A. and Usami, K. and Polzik, E. S.} } @conference { ISI:000355262502116, title = {Photonic temperature sensor based on microring resonators}, booktitle = {2013 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO)}, series = {Conference on Lasers and Electro-Optics}, year = {2013}, note = {Conference on Lasers and Electro-Optics (CLEO), San Jose, CA, JUN 09-14, 2013}, isbn = {978-1-55752-973-2}, issn = {2160-9020}, author = {Xu, H. and M. Hafezi and J. Fan and Migdall, A. and Strouse, G. and Ahmed, Z. and Taylor, J. M.} } @article { ISI:000316412900002, title = {Polarizabilities, Stark shifts, and lifetimes of the In atom}, journal = {PHYSICAL REVIEW A}, volume = {87}, number = {3}, year = {2013}, month = {MAR 21}, issn = {1050-2947}, doi = {10.1103/PhysRevA.87.032513}, author = {Safronova, M. S. and Safronova, U. I. and Porsev, S. G.} } @article { ISI:000324232600003, title = {Quantum Catalysis of Magnetic Phase Transitions in a Quantum Simulator}, journal = {Phys. Rev. Lett.}, volume = {111}, number = {10}, year = {2013}, month = {SEP 5}, pages = {100506}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.111.100506}, author = {Phil Richerme and Crystal Senko and Simcha Korenblit and J Smith and A Lee and Rajibul Islam and W C Campbell and Christopher Monroe} } @article { ISI:000315727700009, title = {Quantum interference and light polarization effects in unresolvable atomic lines: Application to a precise measurement of the Li-6,Li-7 D-2 lines}, journal = {Phys. Rev. A}, volume = {87}, number = {3}, year = {2013}, month = {MAR 7}, issn = {1050-2947}, doi = {10.1103/PhysRevA.87.032504}, author = {Roger C Brown and Wu, Saijun and J V Porto and Sansonetti, Craig J. and C E Simien and Brewer, Samuel M. and Tan, Joseph N. and J D Gillaspy} } @article {2337, title = {A quantum logic gate between a solid-state quantum bit and a photon}, journal = {Nature Photonics}, volume = {7}, year = {2013}, pages = {373}, doi = {10.1038/nphoton.2013.48}, url = {http://www.nature.com/nphoton/journal/v7/n5/full/nphoton.2013.48.html}, author = {Kim, Hyochul and Ranojoy Bose and Thomas C Shen and Glenn S Solomon and Edo Waks} } @conference { ISI:000336029200008, title = {Quantum Networks with Atoms and Photons}, booktitle = {21ST INTERNATIONAL CONFERENCE ON LASER SPECTROSCOPY - ICOLS 2013}, series = {Journal of Physics Conference Series}, volume = {467}, year = {2013}, note = {21st International Conference on Laser Spectroscopy (ICOLS), Univ Calif, Berkeley, CA, JUN 09-14, 2013}, issn = {1742-6588}, doi = {10.1088/1742-6596/467/1/012008}, author = {C. Monroe and Campbell, W. and Cao, C. and Choi, T. and Clark, S. and Debnath, S. and Figgatt, C. and Hayes, D. and Hucul, D. and Inlek, V. and Islam, R. and Korenblit, S. and Johnson, K. and Manning, A. and Mizrahi, J. and Neyenhuis, B. and Lee, A. and Richerme, P. and C. Senko and Smith, J. and Wright, K.} } @article { ISI:000323570800009, title = {Raman-Induced Interactions in a Single-Component Fermi Gas Near an s-Wave Feshbach Resonance}, journal = {Phys. Rev. Lett.}, volume = {111}, number = {9}, year = {2013}, month = {AUG 26}, pages = {095301}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.111.095301}, author = {Ross A Williams and Matthew C Beeler and Lindsay J LeBlanc and Karina Jim{\'e}nez-Garc{\'\i}a and Ian B Spielman} } @article { ISI:000320385800002, title = {Rb atoms in a blue-detuned dipole trap: Coherence and ground-state differential ac Stark shift}, journal = {Phys. Rev. A}, volume = {87}, number = {6}, year = {2013}, month = {JUN 14}, pages = {063412}, issn = {1050-2947}, doi = {10.1103/PhysRevA.87.063412}, author = {Dong Sheng and J Zhang and Luis A Orozco} } @article { ISI:000317580200043, title = {Reducing noise in single-photon-level frequency conversion}, journal = {OPTICS LETTERS}, volume = {38}, number = {8}, year = {2013}, month = {APR 15}, pages = {1310-1312}, issn = {0146-9592}, doi = {10.1364/OL.38.001310}, author = {Kuo, Paulina S. and Pelc, Jason S. and Slattery, Oliver and Kim, Yong-Su and Fejer, M. M. and Tang, Xiao} } @article { ISI:000315727700007, title = {Relativistic many-body calculation of energies, lifetimes, polarizabilities, and hyperpolarizabilities in Li-like Be+}, journal = {PHYSICAL REVIEW A}, volume = {87}, number = {3}, year = {2013}, month = {MAR 7}, issn = {1050-2947}, doi = {10.1103/PhysRevA.87.032502}, author = {Safronova, U. I. and Safronova, M. S.} } @article { ISI:000320760800006, title = {Relativistic many-body calculation of energies, oscillator strengths, transition rates, lifetimes, polarizabilities, and quadrupole moment of a Fr-like Th IV ion}, journal = {PHYSICAL REVIEW A}, volume = {87}, number = {6}, year = {2013}, month = {JUN 20}, issn = {1050-2947}, doi = {10.1103/PhysRevA.87.062509}, author = {Safronova, M. S. and Safronova, U. I.} } @article { ISI:000313006100019, title = {Scaling of the Low-Energy Structure in Above-Threshold Ionization in the Tunneling Regime: Theory and Experiment}, journal = {PHYSICAL REVIEW LETTERS}, volume = {110}, number = {1}, year = {2013}, month = {JAN 2}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.110.013001}, author = {Guo, L. and Han, S. S. and Liu, X. and Cheng, Y. and Xu, Z. Z. and J. Fan and Chen, J. and Chen, S. G. and Becker, W. and Blaga, C. I. and DiChiara, A. D. and Sistrunk, E. and Agostini, P. and DiMauro, L. F.} } @article {1922, title = {Simultaneous Spin-Charge Relaxation in Double Quantum Dots}, journal = {Phys. Rev. Lett.}, volume = {110}, year = {2013}, month = {05/2013}, pages = {196803}, chapter = {196803}, keywords = {Quantum Dots, Spin-orbit coupling}, doi = {10.1103/PhysRevLett.110.196803}, url = {http://link.aps.org/doi/10.1103/PhysRevLett.110.196803}, author = {V Srinivasa and K C Nowack and M Shafiei and L M K Vandersypen and Jacob M Taylor} } @conference { ISI:000355316301323, title = {Single quantum dots as photon pair emitters}, booktitle = {2013 CONFERENCE ON AND INTERNATIONAL QUANTUM ELECTRONICS CONFERENCE LASERS AND ELECTRO-OPTICS EUROPE (CLEO EUROPE/IQEC)}, year = {2013}, note = {Conference on Lasers and Electro-Optics Europe \& International Quantum Electronics Conference (CLEO/Europe-IQEC), Munich, GERMANY, MAY 12-16, 2013}, isbn = {978-1-4799-0594-2}, author = {Predojevic, A. and Huber, T. and Jezek, M. and Jayakumar, H. and Kauten, T. and Solomon, G. S. and Filip, R. and Weihs, G.} } @article { ISI:000315727300006, title = {Soliton dynamics of an atomic spinor condensate on a ring lattice}, journal = {Phys. Rev. A}, volume = {87}, number = {3}, year = {2013}, month = {MAR 6}, issn = {1050-2947}, doi = {10.1103/PhysRevA.87.033608}, author = {Indubala Satija and Pando L, Carlos L. and Eite Tiesinga} } @article { ISI:000325547200076, title = {Spectral response of an upconversion detector and spectrometer}, journal = {OPTICS EXPRESS}, volume = {21}, number = {19}, year = {2013}, month = {SEP 23}, pages = {22523-22531}, issn = {1094-4087}, doi = {10.1364/OE.21.022523}, author = {Kuo, Paulina S. and Slattery, Oliver and Kim, Yong-Su and Pelc, Jason S. and Fejer, M. M. and Tang, Xiao} } @article { ISI:000319618000009, title = {Spectroscopy of a Cooper-pair box coupled to a two-level system via charge and critical current}, journal = {Phys. Rev. B}, volume = {87}, number = {17}, year = {2013}, month = {MAY 28}, issn = {1098-0121}, doi = {10.1103/PhysRevB.87.174522}, author = {Zaretskey, V. and B Suri and S Novikov and F C Wellstood and B S Palmer} } @article {1911, title = {The spin Hall effect in a quantum gas}, journal = {Nature}, volume = {498}, year = {2013}, month = {06/2013}, pages = {201}, keywords = {Spin-orbit coupling}, doi = {DOI:10.1038/nature12185}, url = {http://www.nature.com/nature/journal/v498/n7453/full/nature12185.html}, author = {Matthew C Beeler and Ross A Williams and Karina Jim{\'e}nez-Garc{\'\i}a and Lindsay J LeBlanc and Abigail R Perry and Ian B Spielman} } @article { ISI:000321752400022, title = {Spinor Dynamics in an Antiferromagnetic Spin-1 Thermal Bose Gas}, journal = {Phys. Rev. Lett.}, volume = {111}, number = {2}, year = {2013}, month = {JUL 9}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.111.025301}, author = {H K Pechkis and J P Wrubel and Arne Schwettmann and P F Griffin and Ryan Barnett and Eite Tiesinga and Paul D Lett} } @article {Galitski2013, title = {Spin-orbit coupling in quantum gases}, journal = {Nature}, volume = {494}, number = {7435}, year = {2013}, pages = {49}, publisher = {Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.}, abstract = {Spin-orbit coupling links a particle{\textquoteright}s velocity to its quantum-mechanical spin, and is essential in numerous condensed matter phenomena, including topological insulators and Majorana fermions. In solid-state materials, spin-orbit coupling originates from the movement of electrons in a crystal{\textquoteright}s intrinsic electric field, which is uniquely prescribed in any given material. In contrast, for ultracold atomic systems, the engineered {\textquoteright}material parameters{\textquoteright} are tunable: a variety of synthetic spin-orbit couplings can be engineered on demand using laser fields. Here we outline the current experimental and theoretical status of spin-orbit coupling in ultracold atomic systems, discussing unique features that enable physics impossible in any other known setting.

}, keywords = {CMAMO, Multiple Fellows}, issn = {1476-4687}, doi = {10.1038/nature11841}, url = {http://dx.doi.org/10.1038/nature11841}, author = {Victor M Galitski and Ian B Spielman} } @article { ISI:000318151600084, title = {Storage and retrieval of collective excitations on a long-lived spin transition in a rare-earth ion-doped crystal}, journal = {OPTICS EXPRESS}, volume = {21}, number = {8}, year = {2013}, month = {APR 22}, pages = {10087-10094}, issn = {1094-4087}, doi = {10.1364/OE.21.010087}, author = {Goldschmidt, E. A. and Beavan, S. E. and Polyakov, S. V. and Migdall, A. L. and Sellars, M. J.} } @article { ISI:000325779700002, title = {Strain tuning of a quantum dot strongly coupled to a photonic crystal cavity}, journal = {Appl. Phys. Lett.}, volume = {103}, number = {15}, year = {2013}, month = {OCT 7}, pages = {151102 }, issn = {0003-6951}, doi = {10.1063/1.4824712}, author = {Sun, Shuo and Kim, Hyochul and Glenn S Solomon and Edo Waks} } @article {ISI:000319252000001, title = {Superconducting proximity effect in semiconductor nanowires}, journal = {Phys. Rev. B}, volume = {87}, number = {18}, year = {2013}, month = {may}, pages = {180504}, issn = {1098-0121}, doi = {10.1103/PhysRevB.87.180504}, author = {Tudor D Stanescu and S. Das Sarma} } @article { ISI:000317097400005, title = {Thallium 7p lifetimes derived from experimental data and ab initio calculations of scalar polarizabilities}, journal = {PHYSICAL REVIEW A}, volume = {87}, number = {4}, year = {2013}, month = {APR 3}, issn = {1050-2947}, doi = {10.1103/PhysRevA.87.042502}, author = {Safronova, M. S. and Majumder, P. K.} } @conference { ISI:000355262503346, title = {Time-dependent multiphoton emission from a quantum dot.}, booktitle = {2013 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO)}, series = {Conference on Lasers and Electro-Optics}, year = {2013}, note = {Conference on Lasers and Electro-Optics (CLEO), San Jose, CA, JUN 09-14, 2013}, isbn = {978-1-55752-973-2}, issn = {2160-9020}, author = {Polyakov, Sergey V. and Flagg, Edward B. and Thomay, Tim and Solomon, Glenn S.} } @article {ISI:000319019300001, title = {Topological Zero-Energy Modes in Gapless Commensurate Aubry-Andre-Harper Models}, journal = {Phys. Rev. Lett.}, volume = {110}, number = {18}, year = {2013}, month = {may}, pages = {180403}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.110.180403}, author = {Ganeshan, Sriram and Kai Sun and S. Das Sarma} } @article {1909, title = {Ultrafast Spin-Motion Entanglement and Interferometry with a Single Atom}, journal = {Phys. Rev. Lett.}, volume = {103}, year = {2013}, month = {05/13/2013}, pages = {203001}, doi = {10.1103/PhysRevLett.110.203001}, url = {http://prl.aps.org/abstract/PRL/v110/i20/e203001}, author = {J Mizrahi and Crystal Senko and B Neyenhuis and K G Johnson and W C Campbell and C W S Conover and Christopher Monroe} } @article {ISI:000315733600005, title = {Wigner crystallization in two dimensions: Evolution from long-to short-ranged forces}, journal = {Phys. Rev. B}, volume = {87}, number = {12}, year = {2013}, pages = {125109}, abstract = {We study fermions in two dimensions interacting via a long-ranged 1/r potential for small particle separations and a short-ranged 1/r(3) potential for larger separations in comparison to a length scale xi. We compute the energy of the Wigner crystal and of the homogeneous Fermi liquid phases using a variational approach, and determined the phase diagram as a function of density and xi at zero temperature. We discuss the collective modes in the Fermi liquid phase, finite temperature effects on the phase diagram, and possible experimental realizations of this model. DOI: 10.1103/PhysRevB.87.125109

}, keywords = {No Fellows, visitor collaboration}, issn = {1098-0121}, doi = {10.1103/PhysRevB.87.125109}, author = {Benjamin M Fregoso and C A R S{\'a} de Melo} } @article {ISI:000310131300006, title = {Adiabatic continuity between Hofstadter and Chern insulator states}, journal = {Phys. Rev. B}, volume = {86}, number = {16}, year = {2012}, pages = {165129}, keywords = {No Fellows}, issn = {1098-0121}, doi = {10.1103/PhysRevB.86.165129}, author = {Wu, Ying-Hai and J K Jain and Kai Sun} } @article {2536, title = {All-optical tuning of a quantum dot in a coupled cavity system}, journal = {APPLIED PHYSICS LETTERS}, volume = {100}, year = {2012}, month = {JUN 4}, pages = {231107}, issn = {0003-6951}, doi = {10.1063/1.4719065}, author = {Bose, Ranojoy and Cai, Tao and Solomon, Glenn S. and Waks, Edo} } @article { ISI:000310200100018, title = {Atomic Quantum Simulation of Dynamical Gauge Fields Coupled to Fermionic Matter: From String Breaking to Evolution after a Quench}, journal = {PHYSICAL REVIEW LETTERS}, volume = {109}, number = {17}, year = {2012}, month = {OCT 23}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.109.175302}, author = {Banerjee, D. and Dalmonte, M. and Mueller, M. and Rico, E. and Stebler, P. and Wiese, U. -J. and Zoller, P.} } @article {ISI:000300100500020, title = {Avoidance of Majorana Resonances in Periodic Topological Superconductor-Nanowire Structures}, journal = {Phys. Rev. Lett.}, volume = {108}, number = {6}, year = {2012}, month = {feb}, pages = {067001}, abstract = {Semiconducting nanowires in proximity to superconductors are promising experimental systems for Majorana fermions which may ultimately be used as building blocks for topological quantum computers. A serious challenge in the experimental realization of the Majorana fermion in these semiconductor-superconductor-nanowire structures is tuning the semiconductor chemical potential in close proximity to the metallic superconductor. We show that presently realizable structures in experiments with tunable chemical potential lead to Majorana resonances, which are interesting in their own right, but do not manifest non-Abelian statistics. To resolve this crucial barrier to the solid state realization of Majorana fermions, we propose a new topological superconducting array structure where introducing the superconducting proximity effect from adjacent nanowires generates Majorana fermions with non-Abelian statistics.

}, keywords = {2012, Single Fellow}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v108/i6/e067001}, author = {Jay D Sau and Chien-Hung Lin and Hui, Hoi-Yin and S. Das Sarma} } @article {2555, title = {Blackbody Radiation Shifts in Optical Atomic Clocks}, journal = {IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL}, volume = {59}, year = {2012}, month = {MAR}, pages = {439-447}, issn = {0885-3010}, doi = {10.1109/TUFFC.2012.2213}, author = {Safronova, Marianna S. and Kozlov, Mikhail G. and Clark, Charles W.} } @article {2410, title = {Circuit Quantum Electrodynamics with a Spin Qubit}, journal = {Nature}, volume = {490}, year = {2012}, month = {10/2012}, pages = {380-383}, doi = {10.1038/nature11559}, author = {K. D. Petersson and L. W. McFaul and M D Schroer and M. Jung and Jacob M Taylor and A. A. Houck and J. R. Petta} } @article { ISI:000309174100002, title = {Classification and analysis of two-dimensional Abelian fractional topological insulators}, journal = {PHYSICAL REVIEW B}, volume = {86}, number = {11}, year = {2012}, month = {SEP 21}, issn = {1098-0121}, doi = {10.1103/PhysRevB.86.115131}, author = {Levin, Michael and Stern, Ady} } @article { ISI:000299821100005, title = {Competing Topological Orders in the nu=12/5 Quantum Hall State}, journal = {PHYSICAL REVIEW LETTERS}, volume = {108}, number = {3}, year = {2012}, month = {JAN 20}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.108.036806}, author = {Bonderson, Parsa and Feiguin, Adrian E. and Moeller, Gunnar and Slingerland, J. K.} } @article {2411, title = {Composite pulses for robust universal control of singlet-triplet qubits}, journal = {Nature Communications}, volume = {3}, year = {2012}, month = {8/2012}, pages = {997}, doi = {10.1038/ncomms2003}, author = {Wang, Xin and Bishop, Lev S. and J P Kestner and Barnes, Edwin and Kai Sun and S. Das Sarma} } @article { ISI:000310131300004, title = {Density fluctuation effects on the exciton condensate in double-layer graphene}, journal = {PHYSICAL REVIEW B}, volume = {86}, number = {16}, year = {2012}, month = {OCT 22}, issn = {1098-0121}, doi = {10.1103/PhysRevB.86.161412}, author = {Abergel, D. S. L. and Sensarma, R. and S. Das Sarma} } @article { ISI:000307873600058, title = {Dual-channel, single-photon upconversion detector at 1.3 mu m}, journal = {OPTICS EXPRESS}, volume = {20}, number = {17}, year = {2012}, month = {AUG 13}, pages = {19075-19087}, issn = {1094-4087}, doi = {10.1364/OE.20.019075}, author = {Pelc, J. S. and Kuo, Paulina S. and Slattery, Oliver and Ma, Lijun and Tang, Xiao and Fejer, M. M.} } @article {2545, title = {Dynamically slowed collapse of a Bose-Einstein condensate with attractive interactions}, journal = {PHYSICAL REVIEW A}, volume = {86}, year = {2012}, month = {DEC 3}, pages = {063601}, issn = {1050-2947}, doi = {10.1103/PhysRevA.86.063601}, author = {Compton, R. L. and Lin, Y. -J. and Jimenez-Garcia, K. and Porto, J. V. and Ian B Spielman} } @article {2541, title = {Dynamics of Nonclassical Light from a Single Solid-State Quantum Emitter}, journal = {PHYSICAL REVIEW LETTERS}, volume = {109}, year = {2012}, month = {OCT 18}, pages = {163601}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.109.163601}, author = {Flagg, Edward B. and Polyakov, Sergey V. and Thomay, Tim and Solomon, Glenn S.} } @article {ISI:000312837600004, title = {Equilibrium states of open quantum systems in the strong coupling regime}, journal = {Phys. Rev. E}, volume = {86}, number = {6, 1}, year = {2012}, month = {dec}, pages = {061132}, abstract = {In this work we investigate the late-time steady states of open quantum systems coupled to a thermal reservoir in the strong coupling regime. In general such systems do not necessarily relax to a Boltzmann distribution if the coupling to the thermal reservoir is nonvanishing or equivalently if the relaxation time scales are finite. Using a variety of nonequilibrium formalisms valid for non-Markovian processes, we show that starting from a product state of the closed system = system + environment, with the environment in its thermal state, the open system which results from coarse graining the environment will evolve towards an equilibrium state at late times. This state can be expressed as the reduced state of the closed system thermal state at the temperature of the environment. For a linear (harmonic) system and environment, which is exactly solvable, we are able to show in a rigorous way that all multitime correlations of the open system evolve towards those of the closed system thermal state. Multitime correlations are especially relevant in the non-Markovian regime, since they cannot be generated by the dynamics of the single-time correlations. For more general systems, which cannot be exactly solved, we are able to provide a general proof that all single-time correlations of the open system evolve to those of the closed system thermal state, to first order in the relaxation rates. For the special case of a zero-temperature reservoir, we are able to explicitly construct the reduced closed system thermal state in terms of the environmental correlations. DOI:10.1103/PhysRevE.86.061132

}, issn = {1539-3755}, doi = {10.1103/PhysRevE.86.061132}, author = {Y Subasi and C H Fleming and Jacob M Taylor and Bei-Lok Hu} } @article {2539, title = {Exotic Quantum Spin Models in Spin-Orbit-Coupled Mott Insulators}, journal = {PHYSICAL REVIEW LETTERS}, volume = {109}, year = {2012}, month = {AUG 20}, pages = {085303}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.109.085303}, author = {Radic, J. and Di Ciolo, A. and Sun, K. and Victor M Galitski} } @article {Sau2012, title = {Experimental and materials considerations for the topological superconducting state in electron- and hole-doped semiconductors: Searching for non-Abelian Majorana modes in 1D nanowires and 2D heterostructures}, journal = {Phys. Rev. B}, volume = {85}, number = {6}, year = {2012}, month = {feb}, pages = {064512}, keywords = {Single Fellow}, issn = {1098-0121}, doi = {10.1103/PhysRevB.85.064512}, url = {http://prb.aps.org/abstract/PRB/v85/i6/e064512}, author = {Jay D Sau and Tewari, Sumanta and S. Das Sarma} } @article { ISI:000311967000012, title = {An extremely low-noise heralded single-photon source: A breakthrough for quantum technologies}, journal = {APPLIED PHYSICS LETTERS}, volume = {101}, number = {22}, year = {2012}, month = {NOV 26}, issn = {0003-6951}, doi = {10.1063/1.4768288}, author = {Brida, G. and Degiovanni, I. P. and Genovese, M. and Piacentini, F. and Traina, P. and Della Frera, A. and Tosi, A. and Shehata, A. Bahgat and Scarcella, C. and Gulinatti, A. and Ghioni, M. and Polyakov, S. V. and Migdall, A. and Giudice, A.} } @article {ISI:000312486600004, title = {Flux lattices reformulated}, journal = {New J. Phys.}, volume = {14}, year = {2012}, pages = {123022}, keywords = {Single Fellow}, issn = {1367-2630}, doi = {10.1088/1367-2630/14/12/123022}, author = {Gediminas Juzeliunas and Ian B Spielman} } @article { ISI:000309815700008, title = {Intrinsic Electron-Phonon Resistivity of Bi2Se3 in the Topological Regime}, journal = {PHYSICAL REVIEW LETTERS}, volume = {109}, number = {15}, year = {2012}, month = {OCT 15}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.109.166801}, author = {Kim, Dohun and Li, Qiuzi and Syers, Paul and Butch, Nicholas P. and Paglione, Johnpierre and S. Das Sarma and Fuhrer, Michael S.} } @article { ISI:000310853100007, title = {Limit on the Electron Electric Dipole Moment Using Paramagnetic Ferroelectric Eu0.5Ba0.5TiO3}, journal = {PHYSICAL REVIEW LETTERS}, volume = {109}, number = {19}, year = {2012}, month = {NOV 8}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.109.193003}, author = {Eckel, S. and Sushkov, A. O. and Lamoreaux, S. K.} } @article {2414, title = {Low-Photon-Number Optical Switching with a Single Quantum Dot Coupled to a Photonic Crystal Cavity}, journal = {Phys. Rev. Lett.}, volume = {108}, year = {2012}, month = {5/2012}, pages = {227402}, doi = {10.1103/PhysRevLett.108.227402}, author = {Ranojoy Bose and Deepak Sridharan and Kim, Hyochul and Glenn S Solomon and Edo Waks} } @article {2542, title = {Magic wavelengths for optical cooling and trapping of lithium}, journal = {PHYSICAL REVIEW A}, volume = {86}, year = {2012}, month = {OCT 10}, pages = {042505}, issn = {1050-2947}, doi = {10.1103/PhysRevA.86.042505}, author = {Safronova, M. S. and Safronova, U. I. and Clark, Charles W.} } @article {Solomon2012, title = {Manipulating single photons from disparate quantum sources to be indistinguishable [Invited]}, journal = {JOSA B}, volume = {29}, number = {3}, year = {2012}, month = {feb}, pages = {319}, publisher = {OSA}, abstract = {Quantum information networks will likely require different quantum systems for different functionality within the network. Indistinguishable photons can be used to interconnect these different subsystems. We discuss methods for coherently manipulating the single photons from different quantum systems and experimentally demonstrate spatial, temporal, and frequency matching of single photons using quantum dot and heralded parametric downconversion single photons. The bosonic nature of light insures that when two indistinguishable photons are superimposed on a beam splitter, they will form a single two-photon state, a process we call coalescence. This coalescence property can be used as both a fundamental test of indistinguishability and in quantum networks{\textemdash}connecting and propagating quantum information.

}, keywords = {-wire and -dot devices, Micro-optical devices, Nonlinear optical devices, Photon statistics, Quantum communications, Quantum-well, Resonators, Single Fellow}, issn = {0740-3224}, url = {http://josab.osa.org/abstract.cfm?URI=josab-29-3-319}, author = {Glenn S Solomon and Flagg, Edward B. and Sergey V Polyakov and Thomay, Tim and Andreas Muller} } @article { ISI:000305032100003, title = {Measurements of Quasiparticle Tunneling Dynamics in a Band-Gap-Engineered Transmon Qubit}, journal = {PHYSICAL REVIEW LETTERS}, volume = {108}, number = {23}, year = {2012}, month = {JUN 8}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.108.230509}, author = {Sun, L. and DiCarlo, L. and Reed, M. D. and Catelani, G. and Bishop, Lev S. and Schuster, D. I. and Johnson, B. R. and Yang, Ge A. and Frunzio, L. and Glazman, L. and Devoret, M. H. and Schoelkopf, R. J.} } @article {ISI:000303168600001, title = {Momentum relaxation in a semiconductor proximity-coupled to a disordered s-wave superconductor: Effect of scattering on topological superconductivity}, journal = {Phys. Rev. B}, volume = {85}, number = {14}, year = {2012}, pages = {140513}, keywords = {Single Fellow}, issn = {1098-0121}, doi = {10.1103/PhysRevB.85.140513}, author = {Roman M Lutchyn and Tudor D Stanescu and S. Das Sarma} } @article {ISI:000298984700005, title = {Noise correlation scalings: Revisiting the quantum phase transition in incommensurate lattices with hard-core bosons}, journal = {Phys. Rev. A}, volume = {85}, number = {1}, year = {2012}, month = {jan}, pages = {013617}, abstract = {Finite size scalings of the momentum distribution and noise correlations are performed to study Mott insulator, Bose glass, and superfluid quantum phases in hard-core bosons (HCBs) subjected to quasiperiodic disorder. The exponents of the correlation functions at the superfluid to Bose-glass (SF-BG) transition are found to be approximately one half of the ones that characterize the superfluid phase. The derivatives of the peak intensities of the correlation functions with respect to quasiperiodic disorder are shown to diverge at the SF-BG critical point. This behavior does not occur in the corresponding free fermion system, which also exhibits an Anderson-like transition at the same critical point and thus provides a unique experimental tool to locate the phase transition in interacting bosonic systems. We also report on the absence of primary sublattice peaks in the momentum distribution of the superfluid phase for special fillings.

}, keywords = {2012, Multiple JQI Affil., Single Fellow}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v85/i1/e013617}, author = {He, Kai and Indubala Satija and Charles W Clark and A M Rey and Rigol, Marcos} } @article {2412, title = {Observation of a superfluid Hall effect}, journal = {Proceedings of the National Academy of Science}, volume = {109}, year = {2012}, month = {6/2012}, pages = {10811}, doi = {10.1073/pnas.1202579109}, author = {Lindsay J LeBlanc and Karina Jim{\'e}nez-Garc{\'\i}a and Ross A Williams and Matthew C Beeler and Abigail R Perry and William D Phillips and Ian B Spielman} } @article {ISI:000304531100015, title = {Peierls Substitution in an Engineered Lattice Potential}, journal = {Phys. Rev. Lett.}, volume = {108}, number = {21}, year = {2012}, month = {may}, pages = {225303}, abstract = {Artificial gauge fields open the possibility to realize quantum many-body systems with ultracold atoms, by engineering Hamiltonians usually associated with electronic systems. In the presence of a periodic potential, artificial gauge fields may bring ultracold atoms closer to the quantum Hall regime. Here, we describe a one-dimensional lattice derived purely from effective Zeeman shifts resulting from a combination of Raman coupling and radio-frequency magnetic fields. In this lattice, the tunneling matrix element is generally complex. We control both the amplitude and the phase of this tunneling parameter, experimentally realizing the Peierls substitution for ultracold neutral atoms.

}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.108.225303}, author = {Karina Jim{\'e}nez-Garc{\'\i}a and Lindsay J LeBlanc and Ross A Williams and Matthew C Beeler and Abigail R Perry and Ian B Spielman} } @article {2535, title = {Photon collection from a trapped ion-cavity system}, journal = {PHYSICAL REVIEW A}, volume = {85}, year = {2012}, month = {JUN 11}, pages = {062308}, issn = {1050-2947}, doi = {10.1103/PhysRevA.85.062308}, author = {Sterk, J. D. and Luo, L. and Manning, T. A. and Maunz, P. and C. Monroe} } @article {2534, title = {Polarizabilities of Si2+: A benchmark test of theory and experiment}, journal = {PHYSICAL REVIEW A}, volume = {85}, year = {2012}, month = {MAY 14}, pages = {052506}, issn = {1050-2947}, doi = {10.1103/PhysRevA.85.052506}, author = {Safronova, M. S. and Porsev, S. G. and Kozlov, M. G. and Clark, Charles W.} } @article {2409, title = {Precision Measurement of Transition Matrix Elements via Light Shift Cancellation}, journal = {Phys. Rev. Lett.}, volume = {109}, year = {2012}, month = {12/2012}, doi = {10.1103/PhysRevLett.109.243003}, author = {C. D. Herold and V. D. Vaidya and X. Li and Steven L Rolston and J V Porto and Marianna S Safronova} } @article {Tewari2012, title = {Probing a topological quantum critical point in semiconductor-superconductor heterostructures}, journal = {Phys. Rev. B}, volume = {85}, number = {15}, year = {2012}, month = {apr}, pages = {155302}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v85/i15/e155302}, author = {Tewari, Sumanta and Jay D Sau and V W Scarola and Zhang, Chuanwei and S. Das Sarma} } @inbook { ISI:000301676500003, title = {Projected Wavefunctions and High T-c Superconductivity in Doped Mott Insulators}, booktitle = {STRONGLY CORRELATED SYSTEMS: THEORETICAL METHODS}, series = {Springer Series in Solid-State Sciences}, volume = {171}, year = {2012}, pages = {29-64}, isbn = {978-3-642-21831-6}, issn = {0171-1873}, doi = {10.1007/978-3-642-21831-6\_2}, author = {Randeria, Mohit and Sensarma, Rajdeep and Trivedi, Nandini}, editor = {Avella, A and Mancini, F} } @article {ISI:000312830400001, title = {Quantum dynamics of disordered bosons in an optical lattice}, journal = {Phys. Rev. B}, volume = {86}, number = {21}, year = {2012}, month = {dec}, pages = {214207}, issn = {1098-0121}, doi = {10.1103/PhysRevB.86.214207}, author = {Chien-Hung Lin and Sensarma, Rajdeep and K Sengupta and S. Das Sarma} } @article {Yang2012, title = {Quantum phases of disordered flatband lattice fractional quantum Hall systems}, journal = {Phys. Rev. B}, volume = {85}, number = {20}, year = {2012}, month = {may}, pages = {205124}, keywords = {Single Fellow}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v85/i20/e205124}, author = {Yang, Shuo and Kai Sun and S. Das Sarma} } @article {2543, title = {Quantum phases of hard-core bosons in a frustrated honeycomb lattice}, journal = {NEW JOURNAL OF PHYSICS}, volume = {14}, year = {2012}, month = {NOV 29}, pages = {115028}, issn = {1367-2630}, doi = {10.1088/1367-2630/14/11/115028}, author = {Varney, C. N. and Sun, K. and Victor M Galitski and Rigol, M.} } @article { ISI:000307441600014, title = {Quasiparticles, plasmarons, and quantum spectral function in bilayer graphene (vol 84, 041408, 2011)}, journal = {PHYSICAL REVIEW B}, volume = {86}, number = {7}, year = {2012}, month = {AUG 13}, issn = {1098-0121}, doi = {10.1103/PhysRevB.86.079912}, author = {Sensarma, Rajdeep and Hwang, E. H. and S. Das Sarma} } @article {ISI:000299843200014, title = {Quench-induced Mott-insulator-to-superfluid quantum phase transition}, journal = {Phys. Rev. A}, volume = {85}, number = {1}, year = {2012}, month = {jan}, pages = {013644}, abstract = {Mott-insulator-to-superfluid quenches have been used by recent experiments to generate exotic superfluid phases. While the final Hamiltonian following the sudden quench is that of a superfluid, it is not a priori clear whether the final state of the system actually enters the superfluid phase. To understand the nature of the final state the temporal evolution of the momentum distribution is calculated following a Mott-insulator-to-superfluid quench. Using the numerical infinite time-evolving block decimation approach and the analytical rotor model approximation it is established that the one- and two-dimensional Mott insulators following the quench equilibrate to thermal states with spatially short-ranged coherence peaks in the final momentum distribution and therefore are not superfluids. However, in three dimensions a divergence in the momentum distribution indicating the emergence of true superfluid order is found.

}, keywords = {2012, Single Fellow}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v85/i1/e013644}, author = {Jay D Sau and Bin Wang and S. Das Sarma} } @article { ISI:000306995000036, title = {Realizing a robust practical Majorana chain in a quantum-dot-superconductor linear array}, journal = {NATURE COMMUNICATIONS}, volume = {3}, year = {2012}, month = {JUL}, issn = {2041-1723}, doi = {10.1038/ncomms1966}, author = {Sau, Jay D. and S. Das Sarma} } @article { ISI:000299889600002, title = {Resistivity saturation in a weakly interacting two-dimensional Fermi liquid at intermediate temperatures}, journal = {PHYSICAL REVIEW B}, volume = {85}, number = {4}, year = {2012}, month = {JAN 26}, issn = {1098-0121}, doi = {10.1103/PhysRevB.85.041310}, author = {Zhou, Xiaoqing and Schmidt, B. and Engel, L. W. and Gervais, G. and Pfeiffer, L. N. and West, K. W. and S. Das Sarma} } @article {Makogon2012, title = {Spin-charge-density wave in a rounded-square Fermi surface for ultracold atoms}, journal = {EPL}, volume = {97}, number = {3}, year = {2012}, month = {feb}, pages = {33002}, abstract = {We derive and discuss an experimentally realistic model describing ultracold atoms in an optical lattice including a commensurate, but staggered, spin-flip term. The resulting band structure is quite exotic; fermions in the third band have an unusual rounded picture-frame Fermi surface (essentially two concentric squircles), leading to imperfect nesting. We develop a generalized theory describing the spin and charge degrees of freedom simultaneously at the random-field-approximation level, and show that the system can develop a coupled spin-charge-density wave order. Our generic approach can be used to study spin and charge instabilities in many materials, such as high- T c superconductors, organic compounds, graphene, and iron pnictides.}, keywords = {2012, Single Fellow}, issn = {0295-5075}, url = {http://stacks.iop.org/0295-5075/97/i=3/a=33002}, author = {Makogon, D. and Ian B Spielman and C Morais Smith} } @article { ISI:000312693900001, title = {Splitting of the zero-bias conductance peak as smoking gun evidence for the existence of the Majorana mode in a superconductor-semiconductor nanowire}, journal = {PHYSICAL REVIEW B}, volume = {86}, number = {22}, year = {2012}, month = {DEC 21}, issn = {1098-0121}, doi = {10.1103/PhysRevB.86.220506}, author = {S. Das Sarma and Sau, Jay D. and Stanescu, Tudor D.} } @article { ISI:000307538200028, title = {Surface phonons, elastic response, and conformal invariance in twisted kagome lattices}, journal = {PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, volume = {109}, number = {31}, year = {2012}, month = {JUL 31}, pages = {12369-12374}, issn = {0027-8424}, doi = {10.1073/pnas.1119941109}, author = {Sun, Kai and Souslov, Anton and Mao, Xiaoming and Lubensky, T. C.} } @article { ISI:000304806100008, title = {Synthetic 3D Spin-Orbit Coupling}, journal = {PHYSICAL REVIEW LETTERS}, volume = {108}, number = {23}, year = {2012}, month = {JUN 5}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.108.235301}, author = {Anderson, Brandon M. and Juzeliunas, Gediminas and Victor M Galitski and Ian B Spielman} } @article {Dzero2012, title = {Theory of topological Kondo insulators}, journal = {Phys. Rev. B}, volume = {85}, number = {4}, year = {2012}, month = {jan}, pages = {045130}, keywords = {2012}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v85/i4/e045130}, author = {Maxim Dzero and Kai Sun and Coleman, Piers and Victor M Galitski} } @article {PhysRevLett.109.266402, title = {To Close or Not to Close: The Fate of the Superconducting Gap Across the Topological Quantum Phase Transition in Majorana-Carrying Semiconductor Nanowires}, journal = {Phys. Rev. Lett.}, volume = {109}, year = {2012}, month = {Dec}, pages = {266402}, publisher = {American Physical Society}, doi = {10.1103/PhysRevLett.109.266402}, url = {http://link.aps.org/doi/10.1103/PhysRevLett.109.266402}, author = {Tudor D Stanescu and Tewari, Sumanta and Jay D Sau and S. Das Sarma} } @article {ISI:000312834100003, title = {Topological flat band models with arbitrary Chern numbers}, journal = {Phys. Rev. B}, volume = {86}, number = {24}, year = {2012}, month = {dec}, pages = {241112}, issn = {1098-0121}, doi = {10.1103/PhysRevB.86.241112}, author = {Yang, Shuo and Zheng-Cheng Gu and Kai Sun and S. Das Sarma} } @article {2538, title = {Topological minigap in quasi-one-dimensional spin-orbit-coupled semiconductor Majorana wires}, journal = {PHYSICAL REVIEW B}, volume = {86}, year = {2012}, month = {JUL 5}, pages = {024504}, issn = {1098-0121}, doi = {10.1103/PhysRevB.86.024504}, author = {Tewari, Sumanta and Stanescu, T. D. and Sau, Jay D. and S. Das Sarma} } @article { ISI:000298423000018, title = {Topological semimetal in a fermionic optical lattice}, journal = {NATURE PHYSICS}, volume = {8}, number = {1}, year = {2012}, month = {JAN}, pages = {67-70}, issn = {1745-2473}, author = {Sun, Kai and Liu, W. Vincent and Hemmerich, Andreas and S. Das Sarma} } @article { ISI:000301704900011, title = {Valley-Based Noise-Resistant Quantum Computation Using Si Quantum Dots}, journal = {PHYSICAL REVIEW LETTERS}, volume = {108}, number = {12}, year = {2012}, month = {MAR 20}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.108.126804}, author = {Culcer, Dimitrie and Saraiva, A. L. and Koiller, Belita and Hu, Xuedong and S. Das Sarma} } @article {PhysRevLett.109.230802, title = {Ytterbium in Quantum Gases and Atomic Clocks: van der Waals Interactions and Blackbody Shifts}, journal = {Phys. Rev. Lett.}, volume = {109}, number = {23}, year = {2012}, pages = {230802}, publisher = {American Physical Society}, doi = {10.1103/PhysRevLett.109.230802}, url = {http://link.aps.org/doi/10.1103/PhysRevLett.109.230802}, author = {Marianna S Safronova and S G Porsev and Charles W Clark} } @article {ISI:000312364700008, title = {Zero-bias conductance peak in Majorana wires made of semiconductor/superconductor hybrid structures}, journal = {Phys. Rev. B}, volume = {86}, number = {22}, year = {2012}, month = {dec}, pages = {224511}, issn = {1098-0121}, doi = {10.1103/PhysRevB.86.224511}, author = {Chien-Hung Lin and Jay D Sau and S. Das Sarma} } @article {2553, title = {On- and off-resonance second-harmonic generation in GaAs microdisks}, journal = {OPTICS EXPRESS}, volume = {19}, year = {2011}, month = {AUG 29}, pages = {16898-16918}, issn = {1094-4087}, author = {Kuo, Paulina S. and Solomon, Glenn S.} } @article {Li2011, title = {Anisotropic surface transport in topological insulators in proximity to a helical spin density wave}, journal = {Phys. Rev. B}, volume = {83}, number = {8}, year = {2011}, month = {feb}, pages = {085110}, keywords = {Single Fellow}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v83/i8/e085110}, author = {Li, Qiuzi and Ghosh, Parag and Jay D Sau and Tewari, Sumanta and S. Das Sarma} } @article {Spielman2011a, title = {Atomic physics: A route to quantum magnetism}, journal = {Nature}, volume = {472}, number = {7343}, year = {2011}, month = {apr}, pages = {301{\textendash}2}, publisher = {Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.}, keywords = {Single Fellow}, issn = {1476-4687}, url = {http://dx.doi.org/10.1038/nature10101}, author = {Ian B Spielman} } @article {Powell2011a, title = {Bogoliubov theory of interacting bosons on a lattice in a synthetic magnetic field}, journal = {Phys. Rev. A}, volume = {83}, number = {1}, year = {2011}, month = {jan}, pages = {013612}, keywords = {2011, Single Fellow}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v83/i1/e013612}, author = {Powell, Stephen and Ryan Barnett and Sensarma, Rajdeep and S. Das Sarma} } @article {Zhao2011, title = {Chern numbers hiding in time-of-flight images}, journal = {Phys. Rev. A}, volume = {84}, number = {6}, year = {2011}, month = {dec}, pages = {063629}, abstract = {We present a technique for detecting topological invariants {\textendash} Chern numbers {\textendash} from time-of-flight images of ultra-cold atoms. We show that the Chern numbers of integer quantum Hall states of lattice fermions leave their fingerprints in the atoms{\textquoteright} momentum distribution. We analytically demonstrate that the number of local maxima in the momentum distribution is equal to the Chern number in two limiting cases, for large hopping anisotropy and in the continuum limit. In addition, our numerical simulations beyond these two limits show that these local maxima persist for a range of parameters. Thus, an everyday observable in cold atom experiments can serve as a useful tool to characterize and visualize quantum states with non-trivial topology.

}, keywords = {2011, Multiple Fellows}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v84/i6/e063629 http://arxiv.org/abs/1105.3100}, author = {Zhao, Erhai and Bray-Ali, Noah and Carl J Williams and Ian B Spielman and Indubala Satija} } @article {Sau2011, title = {Chiral Rashba spin textures in ultracold Fermi gases}, journal = {Phys. Rev. B}, volume = {83}, number = {14}, year = {2011}, month = {apr}, pages = {140510}, keywords = {2011, CMAMO, Multiple Fellows}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v83/i14/e140510}, author = {Jay D Sau and Sensarma, Rajdeep and Powell, Stephen and Ian B Spielman and S. Das Sarma} } @article {ISI:000296287300010, title = {Coalescence of Single Photons Emitted by Disparate Single-Photon Sources: The Example of InAs Quantum Dots and Parametric Down-Conversion Sources}, journal = {Phys. Rev. Lett.}, volume = {107}, number = {15}, year = {2011}, month = {oct}, pages = {157402}, abstract = {Single photons produced by fundamentally dissimilar physical processes will in general not be indistinguishable. We show how photons produced from a quantum dot and by parametric down-conversion in a nonlinear crystal can be manipulated to be indistinguishable. The measured two-photon coalescence probability is 16\%, and is limited by quantum-dot decoherence. Temporal filtering to the quantum-dot coherence time and accounting for detector time response increases this to 61\% while retaining 25\% of the events. This technique can connect different elements in a scalable quantum network.

}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.107.157402}, author = {Sergey V Polyakov and Andreas Muller and Flagg, Edward B. and Alexander Ling and Borjemscaia, Natalia and Edward Van Keuren and Alan L Migdall and Glenn S Solomon} } @article { ISI:000286878500002, title = {Competition between Pairing and Ferromagnetic Instabilities in Ultracold Fermi Gases near Feshbach Resonances}, journal = {PHYSICAL REVIEW LETTERS}, volume = {106}, number = {5}, year = {2011}, month = {FEB 1}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.106.050402}, author = {Pekker, David and Babadi, Mehrtash and Sensarma, Rajdeep and Zinner, Nikolaj and Pollet, Lode and Zwierlein, Martin W. and Demler, Eugene} } @article {Sau2011b, title = {Controlling non-Abelian statistics of Majorana fermions in semiconductor nanowires}, journal = {Phys. Rev. B}, volume = {84}, number = {9}, year = {2011}, month = {sep}, pages = {094505}, keywords = {2011, Single Fellow}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v84/i9/e094505}, author = {Jay D Sau and Clarke, David and Tewari, Sumanta} } @article { ISI:000298562600003, title = {Coulomb drag in monolayer and bilayer graphene}, journal = {PHYSICAL REVIEW B}, volume = {84}, number = {24}, year = {2011}, month = {DEC 22}, issn = {1098-0121}, doi = {10.1103/PhysRevB.84.245441}, author = {Hwang, E. H. and Sensarma, Rajdeep and S. Das Sarma} } @article {Sau2011a, title = {Diamagnetic Susceptibility Obtained from the Six-Vertex Model and Its Implications for the High-Temperature Diamagnetic State of Cuprate Superconductors}, journal = {Phys. Rev. Lett.}, volume = {107}, number = {17}, year = {2011}, month = {oct}, pages = {177006}, keywords = {2011, No Fellows}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v107/i17/e177006}, author = {Jay D Sau and Tewari, Sumanta} } @article { ISI:000287365100004, title = {Effects of disorder on magnetic vortex gyration}, journal = {PHYSICAL REVIEW B}, volume = {83}, number = {6}, year = {2011}, month = {FEB 15}, issn = {1098-0121}, doi = {10.1103/PhysRevB.83.064411}, author = {Min, Hongki and McMichael, R. D. and Miltat, Jacques and Stiles, M. D.} } @article { ISI:000289742100023, title = {Electrodynamic and Excitonic Intertube Interactions in Semiconducting Carbon Nanotube Aggregates}, journal = {ACS NANO}, volume = {5}, number = {4}, year = {2011}, month = {APR}, pages = {2611-2618}, issn = {1936-0851}, doi = {10.1021/nn200427r}, author = {Crochet, Jared J. and Sau, Jay D. and Duque, Juan G. and Doorn, Stephen K. and Cohen, Marvin L.} } @article { ISI:000298559600005, title = {Exactly soluble models for fractional topological insulators in two and three dimensions}, journal = {PHYSICAL REVIEW B}, volume = {84}, number = {23}, year = {2011}, month = {DEC 27}, issn = {1098-0121}, doi = {10.1103/PhysRevB.84.235145}, author = {Levin, Michael and Burnell, F. J. and Koch-Janusz, Maciej and Stern, Ady} } @article {2457, title = {Fractional quantum Hall effect in the absence of Landau levels}, journal = {Nature Communications}, volume = {2}, year = {2011}, month = {7/2011}, pages = {389}, doi = {10.1038/ncomms1380}, author = {Dong Sheng and Zheng-Cheng Gu and Kai Sun and L. Sheng} } @article { ISI:000293702200001, title = {Gutzwiller-projected wave functions for the pseudogap state of underdoped high-temperature superconductors}, journal = {PHYSICAL REVIEW B}, volume = {84}, number = {6}, year = {2011}, month = {AUG 9}, issn = {1098-0121}, doi = {10.1103/PhysRevB.84.060503}, author = {Sensarma, Rajdeep and Victor M Galitski} } @article {Hui2011, title = {Instabilities of bosonic spin currents in optical lattices}, journal = {Phys. Rev. A}, volume = {84}, number = {4}, year = {2011}, month = {oct}, pages = {043615}, keywords = {2011, Single Fellow}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v84/i4/e043615}, author = {Hui, Hoi-Yin and Ryan Barnett and Sensarma, Rajdeep and S. Das Sarma} } @article { ISI:000296669100003, title = {Intervalley coupling for interface-bound electrons in silicon: An effective mass study}, journal = {PHYSICAL REVIEW B}, volume = {84}, number = {15}, year = {2011}, month = {OCT 27}, issn = {1098-0121}, doi = {10.1103/PhysRevB.84.155320}, author = {Saraiva, A. L. and Calderon, M. J. and Capaz, Rodrigo B. and Hu, Xuedong and S. Das Sarma and Koiller, Belita} } @article {Varney2011, title = {Kaleidoscope of Exotic Quantum Phases in a Frustrated XY Model}, journal = {Phys. Rev. Lett.}, volume = {107}, number = {7}, year = {2011}, month = {aug}, pages = {077201}, keywords = {Multiple JQI Affil., Single Fellow}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v107/i7/e077201}, author = {Varney, Christopher and Kai Sun and Victor M Galitski and Rigol, Marcos} } @article { ISI:000291976300013, title = {Landau levels and band bending in few-layer epitaxial graphene}, journal = {PHYSICAL REVIEW B}, volume = {83}, number = {15}, year = {2011}, month = {APR 18}, issn = {1098-0121}, doi = {10.1103/PhysRevB.83.155430}, author = {Min, Hongki and Adam, S. and Song, Young Jae and Stroscio, Joseph A. and Stiles, M. D. and MacDonald, A. H.} } @article {Bose2011a, title = {Large optical Stark shifts in semiconductor quantum dots coupled to photonic crystal cavities}, journal = {Appl. Phys. Lett.}, volume = {98}, number = {12}, year = {2011}, month = {mar}, pages = {121109}, keywords = {2011, CMAMO, gallium arsenide, III-V semiconductors, indium compounds, master equation, Multiple Fellows, photonic crystals, semiconductor quantum dots, Stark effect}, issn = {00036951}, url = {http://link.aip.org/link/?APPLAB/98/121109/1}, author = {Ranojoy Bose and Deepak Sridharan and Glenn S Solomon and Edo Waks} } @article {2394, title = {Laser Cooling and Optical Detection of Excitations in a LC Electrical Circuit}, journal = {Physical Review Letters}, volume = {107}, year = {2011}, month = {12/2011}, url = {http://link.aps.org/doi/10.1103/PhysRevLett.107.273601}, author = {Jacob M Taylor and Anders S Sorensen and Charles M Marcus and Eugene S Polzik} } @article {Kim2011, title = {Magnetic field tuning of a quantum dot strongly coupled to a photonic crystal cavity}, journal = {Appl. Phys. Lett.}, volume = {98}, number = {9}, year = {2011}, month = {mar}, pages = {091102}, keywords = {2011, diamagnetic materials, excitons, III-V semiconductors, indium compounds, Magnetic semiconductors, Multiple Fellows, photonic crystals, semiconductor quantum dots, Zeeman effect}, issn = {00036951}, url = {http://link.aip.org/link/?APPLAB/98/091102/1}, author = {Kim, Hyochul and Thomas C Shen and Deepak Sridharan and Glenn S Solomon and Edo Waks} } @article { ISI:000293128900003, title = {Majorana fermion exchange in quasi-one-dimensional networks}, journal = {PHYSICAL REVIEW B}, volume = {84}, number = {3}, year = {2011}, month = {JUL 25}, issn = {1098-0121}, doi = {10.1103/PhysRevB.84.035120}, author = {Clarke, David J. and Sau, Jay D. and Tewari, Sumanta} } @article {Clarke2011, title = {Majorana fermion exchange in quasi-one-dimensional networks}, journal = {Phys. Rev. B}, volume = {84}, number = {3}, year = {2011}, month = {jul}, pages = {035120}, keywords = {2011, No Fellows}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v84/i3/e035120}, author = {Clarke, David and Jay D Sau and Tewari, Sumanta} } @article {Stanescu2011, title = {Majorana fermions in semiconductor nanowires}, journal = {Phys. Rev. B}, volume = {84}, number = {14}, year = {2011}, month = {oct}, pages = {144522}, keywords = {2011, Single Fellow}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v84/i14/e144522}, author = {Tudor D Stanescu and Roman M Lutchyn and S. Das Sarma} } @article {Sedrakyan2011, title = {Majorana path integral for nonequilibrium dynamics of two-level systems}, journal = {Phys. Rev. B}, volume = {83}, number = {13}, year = {2011}, month = {apr}, pages = {134303}, keywords = {2011, Single Fellow}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v83/i13/e134303}, author = {Tigran Sedrakyan and Victor M Galitski} } @article {Sensarma2011, title = {Momentum-resolved optical lattice modulation spectroscopy for bosons in optical lattices}, journal = {Phys. Rev. B}, volume = {84}, number = {8}, year = {2011}, month = {aug}, pages = {081101}, keywords = {2011, Single Fellow}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v84/i8/e081101}, author = {Sensarma, Rajdeep and K Sengupta and S. Das Sarma} } @article { ISI:000293830900001, title = {Momentum-resolved optical lattice modulation spectroscopy for bosons in optical lattices}, journal = {PHYSICAL REVIEW B}, volume = {84}, number = {8}, year = {2011}, month = {AUG 15}, issn = {1098-0121}, doi = {10.1103/PhysRevB.84.081101}, author = {Sensarma, Rajdeep and Sengupta, K. and S. Das Sarma} } @article {Sun2011a, title = {Nearly Flatbands with Nontrivial Topology}, journal = {Phys. Rev. Lett.}, volume = {106}, number = {23}, year = {2011}, month = {jun}, pages = {236803}, keywords = {2011, Single Fellow}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v106/i23/e236803}, author = {Kai Sun and Zheng-Cheng Gu and Katsura, Hosho and S. Das Sarma} } @article { ISI:000293128900013, title = {Nonmonotonic temperature dependent transport in graphene grown by chemical vapor deposition}, journal = {PHYSICAL REVIEW B}, volume = {84}, number = {3}, year = {2011}, month = {JUL 25}, issn = {1098-0121}, doi = {10.1103/PhysRevB.84.035421}, author = {Heo, J. and Chung, H. J. and Lee, Sung-Hoon and Yang, H. and Seo, D. H. and Shin, J. K. and Chung, U-In and Seo, S. and Hwang, E. H. and S. Das Sarma} } @article {Sau2011c, title = {Number conserving theory for topologically protected degeneracy in one-dimensional fermions}, journal = {Phys. Rev. B}, volume = {84}, number = {14}, year = {2011}, month = {oct}, pages = {144509}, keywords = {2011, Single Fellow}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v84/i14/e144509}, author = {Jay D Sau and B I Halperin and Flensberg, K. and S. Das Sarma} } @article { ISI:000297795900001, title = {Observation of High Coherence in Josephson Junction Qubits Measured in a Three-Dimensional Circuit QED Architecture}, journal = {PHYSICAL REVIEW LETTERS}, volume = {107}, number = {24}, year = {2011}, month = {DEC 5}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.107.240501}, author = {Paik, Hanhee and Schuster, D. I. and Bishop, Lev S. and Kirchmair, G. and Catelani, G. and Sears, A. P. and Johnson, B. R. and Reagor, M. J. and Frunzio, L. and Glazman, L. I. and Girvin, S. M. and Devoret, M. H. and Schoelkopf, R. J.} } @article {Bose2011, title = {Observation of strong coupling through transmission modification of a cavity-coupled photonic crystal waveguide}, journal = {Optics Express}, volume = {19}, number = {6}, year = {2011}, month = {mar}, pages = {5398}, publisher = {OSA}, abstract = {We investigate strong coupling between a single quantum dot (QD) and photonic crystal cavity through transmission modification of an evanescently coupled waveguide. Strong coupling is observed through modification of both the cavity scattering spectrum and waveguide transmission. We achieve an overall Q of 5800 and an exciton-photon coupling strength of 21 GHz for this integrated cavity-waveguide structure. The transmission contrast for the bare cavity mode is measured to be 24\%. These results represent important progress towards integrated cavity quantum electrodynamics using a planar photonic architecture.}, keywords = {2011, CMAMO, Integrated optics devices, Multiple Fellows, Quantum electrodynamics}, issn = {1094-4087}, url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-19-6-5398}, author = {Ranojoy Bose and Deepak Sridharan and Glenn S Solomon and Edo Waks} } @article {Spielman2011a, title = {An optical lattice of flux}, journal = {Physics}, volume = {4}, year = {2011}, month = {apr}, pages = {35}, keywords = {2011, Single Fellow}, issn = {1943-2879}, url = {http://physics.aps.org/articles/v4/35}, author = {Ian B Spielman} } @article {Borkowski2011, title = {Photoassociative production of ultracold heteronuclear ytterbium molecules}, journal = {Phys. Rev. A}, volume = {84}, number = {3}, year = {2011}, month = {sep}, pages = {30702}, keywords = {2011, Coherent control of atomic interactions with photo, General theories and models of atomic and molecula, Interatomic potentials and forces, Laser-modified scattering and reactions}, issn = {1050-2947}, url = {http://adsabs.harvard.edu/abs/2011PhRvA..84c0702B}, author = {Mateusz Borkowski and Roman Ciurylo and Paul S Julienne and Yamazaki, Rekishu and Hara, Hideaki and Katsunari Enomoto and Taie, Shintaro and Seiji Sugawa and Takasu, Yosuke and Yoshiro Takahashi} } @article {2554, title = {Precision Calculation of Blackbody Radiation Shifts for Optical Frequency Metrology}, journal = {PHYSICAL REVIEW LETTERS}, volume = {107}, year = {2011}, month = {SEP 30}, pages = {143006}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.107.143006}, author = {Safronova, M. S. and Kozlov, M. G. and Clark, Charles W.} } @article { ISI:000290162000003, title = {Prediction of a gapless topological Haldane liquid phase in a one-dimensional cold polar molecular lattice}, journal = {PHYSICAL REVIEW B}, volume = {83}, number = {17}, year = {2011}, month = {MAY 3}, issn = {1098-0121}, doi = {10.1103/PhysRevB.83.174409}, author = {Kestner, J. P. and Wang, Bin and Sau, Jay D. and S. Das Sarma} } @article {Sau2011d, title = {Probing non-Abelian statistics with Majorana fermion interferometry in spin-orbit-coupled semiconductors}, journal = {Phys. Rev. B}, volume = {84}, number = {8}, year = {2011}, month = {aug}, pages = {085109}, keywords = {2011, Single Fellow}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v84/i8/e085109}, author = {Jay D Sau and Tewari, Sumanta and S. Das Sarma} } @article {Sedrakyan2011a, title = {Proposed signature of Anderson localization and correlation-induced delocalization in an N-leg optical lattice}, journal = {Phys. Rev. A}, volume = {84}, number = {5}, year = {2011}, month = {nov}, pages = {053621}, keywords = {2011, Single Fellow}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v84/i5/e053621}, author = {Tigran Sedrakyan and J P Kestner and S. Das Sarma} } @article {Varney2011, title = {Publisher{\textquoteright}s Note: Kaleidoscope of Exotic Quantum Phases in a Frustrated XY Model [Phys. Rev. Lett. 107, 077201 (2011)]}, journal = {Phys. Rev. Lett.}, volume = {107}, number = {7}, year = {2011}, month = {aug}, pages = {077201}, keywords = {2011, Multiple JQI Affil., Single Fellow}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v107/i8/e089902 http://prl.aps.org/abstract/PRL/v107/i7/e077201}, author = {Varney, Christopher and Kai Sun and Victor M Galitski and Rigol, Marcos} } @article {Barnett2011, title = {Quantum rotor theory of spinor condensates in tight traps}, journal = {Phys. Rev. A}, volume = {83}, number = {2}, year = {2011}, month = {feb}, pages = {023613}, keywords = {2011, Single Fellow}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v83/i2/e023613}, author = {Ryan Barnett and Hui, Hoi-Yin and Chien-Hung Lin and Jay D Sau and S. Das Sarma} } @article { ISI:000293921000017, title = {Quantum-Classical Crossover and Apparent Metal-Insulator Transition in a Weakly Interacting 2D Fermi Liquid}, journal = {PHYSICAL REVIEW LETTERS}, volume = {107}, number = {8}, year = {2011}, month = {AUG 16}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.107.086804}, author = {Zhou, Xiaoqing and Schmidt, B. and Proust, C. and Gervais, G. and Pfeiffer, L. N. and West, K. W. and S. Das Sarma} } @article { ISI:000293129300001, title = {Quasiparticles, plasmarons, and quantum spectral function in bilayer graphene}, journal = {PHYSICAL REVIEW B}, volume = {84}, number = {4}, year = {2011}, month = {JUL 25}, issn = {1098-0121}, doi = {10.1103/PhysRevB.84.041408}, author = {Sensarma, Rajdeep and Hwang, E. H. and S. Das Sarma} } @article {2552, title = {Realistic Rashba and Dresselhaus spin-orbit coupling for neutral atoms}, journal = {PHYSICAL REVIEW A}, volume = {84}, year = {2011}, month = {AUG 30}, pages = {025602}, issn = {1050-2947}, doi = {10.1103/PhysRevA.84.025602}, author = {Campbell, D. L. and Juzeliunas, G. and Ian B Spielman} } @article { ISI:000295285800004, title = {Relaxation of Fermionic Excitations in a Strongly Attractive Fermi Gas in an Optical Lattice}, journal = {PHYSICAL REVIEW LETTERS}, volume = {107}, number = {14}, year = {2011}, month = {SEP 27}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.107.145303}, author = {Sensarma, Rajdeep and Pekker, David and Rey, Ana Maria and Lukin, Mikhail D. and Demler, Eugene} } @article {Sridharan2011, title = {A reversibly tunable photonic crystal nanocavity laser using photochromic thin film}, journal = {Optics Express}, volume = {19}, number = {6}, year = {2011}, month = {mar}, pages = {5551}, publisher = {OSA}, abstract = {We demonstrate a reversibly tunable photonic crystal quantum dot laser using a photochromic thin film. The laser is composed of a photonic crystal cavity with a bare cavity Q as high as 4500 coupled to a high density ensemble of indium arsenide quantum dots. By depositing a thin layer of photochromic material on the photonic crystal cavities, the laser can be optically tuned smoothly and reversibly over a wavelength range of 2.68 nm. Lasing is observed at temperatures as high as 80 K in the 900-1000 nm near-infrared wavelength range. The spontaneous emission coupling factor is measured to be as high as $\beta$ = 0.41, indicating that the laser operates in the high-$\beta$ regime.}, keywords = {2011, CMAMO, Lasers, Multiple Fellows, Nanophotonics and photonic crystals, tunable}, issn = {1094-4087}, url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-19-6-5551}, author = {Deepak Sridharan and Ranojoy Bose and Kim, Hyochul and Glenn S Solomon and Edo Waks} } @article {Lutchyn2011a, title = {Search for Majorana Fermions in Multiband Semiconducting Nanowires}, journal = {Phys. Rev. Lett.}, volume = {106}, number = {12}, year = {2011}, month = {mar}, pages = {127001}, keywords = {2011, Single Fellow}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v106/i12/e127001}, author = {Roman M Lutchyn and Tudor D Stanescu and S. Das Sarma} } @article { ISI:000290478200001, title = {Semiclassical Boltzmann transport theory for graphene multilayers}, journal = {PHYSICAL REVIEW B}, volume = {83}, number = {19}, year = {2011}, month = {MAY 11}, issn = {1098-0121}, doi = {10.1103/PhysRevB.83.195117}, author = {Min, Hongki and Jain, Parakh and Adam, S. and Stiles, M. D.} } @article {Lin2011, title = {Spin-orbit-coupled Bose-Einstein condensates}, journal = {Nature}, volume = {471}, number = {7336}, year = {2011}, month = {mar}, pages = {83{\textendash}6}, publisher = {Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.}, abstract = {Spin-orbit (SO) coupling{\textendash}the interaction between a quantum particle{\textquoteright}s spin and its momentum{\textendash}is ubiquitous in physical systems. In condensed matter systems, SO coupling is crucial for the spin-Hall effect and topological insulators; it contributes to the electronic properties of materials such as GaAs, and is important for spintronic devices. Quantum many-body systems of ultracold atoms can be precisely controlled experimentally, and would therefore seem to provide an ideal platform on which to study SO coupling. Although an atom{\textquoteright}s intrinsic SO coupling affects its electronic structure, it does not lead to coupling between the spin and the centre-of-mass motion of the atom. Here, we engineer SO coupling (with equal Rashba and Dresselhaus strengths) in a neutral atomic Bose-Einstein condensate by dressing two atomic spin states with a pair of lasers. Such coupling has not been realized previously for ultracold atomic gases, or indeed any bosonic system. Furthermore, in the presence of the laser coupling, the interactions between the two dressed atomic spin states are modified, driving a quantum phase transition from a spatially spin-mixed state (lasers off) to a phase-separated state (above a critical laser intensity). We develop a many-body theory that provides quantitative agreement with the observed location of the transition. The engineered SO coupling{\textendash}equally applicable for bosons and fermions{\textendash}sets the stage for the realization of topological insulators in fermionic neutral atom systems.}, keywords = {2011, Single Fellow}, issn = {1476-4687}, url = {http://dx.doi.org/10.1038/nature09887}, author = {Y -J Lin and Karina Jim{\'e}nez-Garc{\'\i}a and Ian B Spielman} } @article {Kim2011a, title = {Strong coupling between two quantum dots and a photonic crystal cavity using magnetic field tuning}, journal = {Optics Express}, volume = {19}, number = {3}, year = {2011}, month = {jan}, pages = {2589}, publisher = {OSA}, abstract = {We demonstrate strong coupling between two indium arsenide (InAs) quantum dots (QDs) and a photonic crystal cavity by using a magnetic field as a frequency tuning method. The magnetic field causes a red shift of an exciton spin state in one QD and a blue shift in the opposite exciton spin state of the second QD, enabling them to be simultaneously tuned to the same cavity resonance. This method can match the emission frequency of two QDs separated by detunings as large as 1.35 meV using a magnetic field of up to 7 T. By controlling the detuning between the two QDs we measure the vacuum Rabi splitting (VRS) both when the QDs are individually coupled to the cavity, as well as when they are coupled to the cavity simultaneously. In the latter case the oscillator strength of two QDs shows a collective behavior, resulting in enhancement of the VRS as compared to the individual cases. Experimental results are compared to theoretical calculations based on the solution to the full master equation and found to be in excellent agreement.

}, keywords = {2011, Magneto-optic systems, Multiple Fellows, photonic crystals, Quantum electrodynamics}, issn = {1094-4087}, url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-19-3-2589}, author = {Kim, Hyochul and Deepak Sridharan and Thomas C Shen and Glenn S Solomon and Edo Waks} } @article {Lin2011b, title = {A synthetic electric force acting on neutral atoms}, journal = {Nat. Phys.}, volume = {7}, number = {7}, year = {2011}, month = {mar}, pages = {531{\textendash}534}, publisher = {Nature Publishing Group}, keywords = {2011, Multiple Fellows}, issn = {1745-2473}, url = {http://dx.doi.org/10.1038/nphys1954}, author = {Y -J Lin and R L Compton and Karina Jim{\'e}nez-Garc{\'\i}a and William D Phillips and J V Porto and Ian B Spielman} } @article {Williams2011, title = {Synthetic Partial Waves in Ultracold Atomic Collisions}, journal = {Science}, volume = {335}, number = {6066}, year = {2011}, month = {dec}, pages = {314{\textendash}317}, abstract = {Interactions between particles can be strongly altered by their environment. We demonstrate a technique for modifying interactions between ultracold atoms by dressing the bare atomic states with light, creating an effective interaction of vastly increased range that scatters states of finite relative angular momentum at collision energies where only s-wave scattering would normally be expected. We collided two optically dressed neutral atomic Bose-Einstein condensates with equal, and opposite, momenta and observed that the usual s-wave distribution of scattered atoms was altered by the appearance of d- and g-wave contributions. This technique is expected to enable quantum simulation of exotic systems, including those predicted to support Majorana fermions.

}, keywords = {2011, Multiple Fellows}, issn = {1095-9203}, url = {http://www.sciencemag.org/content/335/6066/314.abstract}, author = {Ross A Williams and Lindsay J LeBlanc and Karina Jim{\'e}nez-Garc{\'\i}a and Matthew C Beeler and Abigail R Perry and William D Phillips and Ian B Spielman} } @article {Varney2011a, title = {Topological phase transitions for interacting finite systems}, journal = {Phys. Rev. B}, volume = {84}, number = {24}, year = {2011}, month = {dec}, pages = {241105}, keywords = {2011, Multiple JQI Affil., Single Fellow}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v84/i24/e241105}, author = {Varney, Christopher and Kai Sun and Rigol, Marcos and Victor M Galitski} } @article {Sun2011, title = {Topological semimetal in a fermionic optical lattice}, journal = {Nature Physics}, volume = {8}, number = {1}, year = {2011}, month = {nov}, pages = {67{\textendash}70}, publisher = {Nature Publishing Group}, keywords = {2011}, issn = {1745-2473}, doi = {10.1038/nphys2134}, author = {Kai Sun and W V Liu and Hemmerich, Andreas and S. Das Sarma} } @article {Tewari2011, title = {Topologically non-trivial superconductivity in spin{\textendash}orbit-coupled systems: bulk phases and quantum phase transitions}, journal = {New J. Phys.}, volume = {13}, number = {6}, year = {2011}, month = {jun}, pages = {065004}, abstract = {Topologically non-trivial superconductivity has been predicted to occur in superconductors with a sizable spin-orbit coupling in the presence of an external Zeeman splitting. Two such systems have been proposed: (a) s-wave superconductor pair potential is proximity induced on a semiconductor, and (b) pair potential naturally arises from an intrinsic s-wave pairing interaction. As is now well known, such systems in the form of a 2D film or 1D nano-wires in a wire-network can be used for topological quantum computation. When the external Zeeman splitting \$\backslash Gamma\$ crosses a critical value \$\backslash Gamma\_c\$, the system passes from a regular superconducting phase to a non-Abelian topological superconducting phase. In both cases (a) and (b) we consider in this paper the pair potential \$\backslash Delta\$ is strictly s-wave in both the ordinary and the topological superconducting phases, which are separated by a topological quantum critical point at \$\backslash Gamma\_c = \backslash sqrt\{\backslash Delta\^{}2 + \backslash mu\^{}2\}\$, where \$\backslash mu (\>\> \backslash Delta)\$ is the chemical potential. On the other hand, since \$\backslash Gamma\_c \>\> \backslash Delta\$, the Zeeman splitting required for the topological phase (\$\backslash Gamma \> \backslash Gamma\_c\$) far exceeds the value (\$\backslash Gamma \backslash sim \backslash Delta\$) above which an s-wave pair potential is expected to vanish (and the system to become non-superconducting) in the absence of spin-orbit coupling. We are thus led to a situation that the topological superconducting phase appears to set in a parameter regime at which the system actually is non-superconducting in the absence of spin-orbit coupling. In this paper we address the question of how a pure s-wave pair potential can survive a strong Zeeman field to give rise to a topological superconducting phase. We show that the spin-orbit coupling is the crucial parameter for the quantum transition into and the robustness of the topologically non-trivial superconducting phase realized for \$\backslash Gamma \>\> \backslash Delta\$.

}, keywords = {2011, Single Fellow}, issn = {1367-2630}, url = {http://stacks.iop.org/1367-2630/13/i=6/a=065004 http://arxiv.org/abs/1012.0057}, author = {Tewari, Sumanta and Tudor D Stanescu and Jay D Sau and S. Das Sarma} } @article {Arora2011, title = {Tune-out wavelengths of alkali-metal atoms and their applications}, journal = {Phys. Rev. A}, volume = {84}, number = {4}, year = {2011}, month = {oct}, pages = {043401}, keywords = {2011, Single Fellow}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v84/i4/e043401}, author = {Arora, Bindiya and Marianna S Safronova and Charles W Clark} } @article {Radic2011, title = {Vortices in spin-orbit-coupled Bose-Einstein condensates}, journal = {Phys. Rev. A}, volume = {84}, number = {6}, year = {2011}, month = {dec}, pages = {063604}, keywords = {2011, CMAMO, Multiple Fellows}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v84/i6/e063604}, author = {Juraj Radi{\'c} and Tigran Sedrakyan and Ian B Spielman and Victor M Galitski} } @article {Barnett2010, title = {Antiferromagnetic spinor condensates are quantum rotors}, journal = {Phys. Rev. A}, volume = {82}, number = {3}, year = {2010}, month = {sep}, keywords = {2010, Multiple Fellows}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v82/i3/e031602}, author = {Ryan Barnett and Jay D Sau and S. Das Sarma} } @article { ISI:000275072500168, title = {BCS-BEC crossover and the disappearance of Fulde-Ferrell-Larkin-Ovchinnikov correlations in a spin-imbalanced one-dimensional Fermi gas}, journal = {PHYSICAL REVIEW A}, volume = {81}, number = {2}, year = {2010}, month = {FEB}, issn = {1050-2947}, doi = {10.1103/PhysRevA.81.023629}, author = {Heidrich-Meisner, F. and Feiguin, A. E. and Schollwoeck, U. and Zwerger, W.} } @article {Sedrakyan2010, title = {Boundary Wess-Zumino-Novikov-Witten model from the pairing Hamiltonian}, journal = {Phys. Rev. B}, volume = {82}, number = {21}, year = {2010}, month = {dec}, keywords = {2010, Single Fellow}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v82/i21/e214502}, author = {Tigran Sedrakyan and Victor M Galitski} } @article {Anderson2010, title = {Bulk manifestation of the spin Hall effect}, journal = {Phys. Rev. B}, volume = {81}, number = {12}, year = {2010}, month = {mar}, keywords = {2010, Single Fellow}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v81/i12/e121304}, author = {Brandon M Anderson and Tudor D Stanescu and Victor M Galitski} } @article {Waks2010, title = {Cavity QED treatment of interactions between a metal nanoparticle and a dipole emitter}, journal = {Phys. Rev. A}, volume = {82}, number = {4}, year = {2010}, month = {oct}, pages = {043845}, keywords = {2010, Single Fellow}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v82/i4/e043845}, author = {Edo Waks and Deepak Sridharan} } @article { ISI:000284205400007, title = {Dynamic screening and low-energy collective modes in bilayer graphene}, journal = {PHYSICAL REVIEW B}, volume = {82}, number = {19}, year = {2010}, month = {NOV 15}, issn = {1098-0121}, doi = {10.1103/PhysRevB.82.195428}, author = {Sensarma, Rajdeep and Hwang, E. H. and S. Das Sarma} } @article {Bryant2010, title = {Effect of Mechanical Strain on the Optical Properties of Quantum Dots: Controlling Exciton Shape, Orientation, and Phase with a Mechanical Strain}, journal = {Phys. Rev. Lett.}, volume = {105}, number = {6}, year = {2010}, month = {aug}, keywords = {2010}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v105/i6/e067404}, author = {Garnett W Bryant and M Zieli{\'n}ski and Natalia Malkova and Sims, James and W Jask{\'o}lski and Javier Aizpurua} } @article {Hayes2010, title = {Entanglement of Atomic Qubits Using an Optical Frequency Comb}, journal = {Phys. Rev. Lett.}, volume = {104}, number = {14}, year = {2010}, month = {apr}, pages = {140501}, keywords = {Single Fellow}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v104/i14/e140501}, author = {David Hayes and D N Matsukevich and P Maunz and D Hucul and Q Quraishi and Steven Olmschenk and W C Campbell and J Mizrahi and Crystal Senko and Christopher Monroe} } @article {Lundblad2010, title = {Experimental observation of magic-wavelength behavior of \^\87\Rb atoms in an optical lattice}, journal = {Phys. Rev. A}, volume = {81}, number = {3}, year = {2010}, month = {mar}, keywords = {2010}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v81/i3/e031611}, author = {Lundblad, N. and Schlosser, M. and J V Porto} } @article {Li2010, title = {Exploring complex phenomena using ultracold atoms in bichromatic lattices}, journal = {Phys. Rev. E}, volume = {82}, number = {1}, year = {2010}, month = {jul}, keywords = {2010}, issn = {1539-3755}, url = {http://pre.aps.org/abstract/PRE/v82/i1/e016217}, author = {Li, Shuming and Indubala Satija and Charles W Clark and A M Rey} } @article { ISI:000274664500043, title = {Fractional Quantum Hall State at nu=5/2 and the Moore-Read Pfaffian}, journal = {PHYSICAL REVIEW LETTERS}, volume = {104}, number = {7}, year = {2010}, month = {FEB 19}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.104.076803}, author = {Storni, M. and Morf, R. H. and S. Das Sarma} } @article {Sau2010b, title = {Generic New Platform for Topological Quantum Computation Using Semiconductor Heterostructures}, journal = {Phys. Rev. Lett.}, volume = {104}, number = {4}, year = {2010}, month = {jan}, pages = {040502}, keywords = {2010, Single Fellow}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v104/i4/e040502}, author = {Jay D Sau and Roman M Lutchyn and Tewari, Sumanta and S. Das Sarma} } @article {2548, title = {Interacting Hofstadter Spectrum of Atoms in an Artificial Gauge Field}, journal = {PHYSICAL REVIEW LETTERS}, volume = {104}, year = {2010}, month = {JUN 25}, pages = {255303}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.104.255303}, author = {Powell, Stephen and Ryan Barnett and Sensarma, Rajdeep and S. Das Sarma} } @article {Varney2010, title = {Interaction effects and quantum phase transitions in topological insulators}, journal = {Phys. Rev. B}, volume = {82}, number = {11}, year = {2010}, month = {sep}, keywords = {2010, Multiple JQI Affil., Single Fellow}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v82/i11/e115125}, author = {Varney, Christopher and Kai Sun and Rigol, Marcos and Victor M Galitski} } @article {Flagg2010, title = {Interference of Single Photons from Two Separate Semiconductor Quantum Dots}, journal = {Phys. Rev. Lett.}, volume = {104}, number = {13}, year = {2010}, month = {apr}, pages = {137401}, keywords = {2010, CMAMO, Multiple Fellows}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v104/i13/e137401}, author = {Flagg, Edward B. and Andreas Muller and Sergey V Polyakov and Alexander Ling and Alan L Migdall and Glenn S Solomon} } @article { ISI:000283839800003, title = {Kelvin formula for thermopower}, journal = {PHYSICAL REVIEW B}, volume = {82}, number = {19}, year = {2010}, month = {NOV 4}, issn = {1098-0121}, doi = {10.1103/PhysRevB.82.195105}, author = {Peterson, Michael R. and Shastry, B. Sriram} } @article { ISI:000286756300001, title = {Lifetime of double occupancies in the Fermi-Hubbard model}, journal = {PHYSICAL REVIEW B}, volume = {82}, number = {22}, year = {2010}, month = {DEC 3}, issn = {1098-0121}, doi = {10.1103/PhysRevB.82.224302}, author = {Sensarma, Rajdeep and Pekker, David and Altman, Ehud and Demler, Eugene and Strohmaier, Niels and Greif, Daniel and Joerdens, Robert and Tarruell, Leticia and Moritz, Henning and Esslinger, Tilman} } @article {Lutchyn2010, title = {Majorana Fermions and a Topological Phase Transition in Semiconductor-Superconductor Heterostructures}, journal = {Phys. Rev. Lett.}, volume = {105}, number = {7}, year = {2010}, pages = {077001}, keywords = {2010, Single Fellow}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.105.077001}, author = {Roman M Lutchyn and Jay D Sau and S. Das Sarma} } @article {Ropp2010, title = {Manipulating quantum dots to nanometer precision by control of flow}, journal = {Nano Lett.}, volume = {10}, number = {7}, year = {2010}, month = {jul}, pages = {2525{\textendash}30}, publisher = {American Chemical Society}, abstract = {We present a method for manipulating preselected quantum dots (QDs) with nanometer precision by flow control. The accuracy of this approach scales more favorably with particle size than optical trapping, enabling more precise positioning of nanoscopic particles. We demonstrate the ability to position a single QD in a 100 microm working region to 45 nm accuracy for holding times exceeding one hour and the ability to take active quantum measurements on the dynamically manipulated QD.

}, keywords = {2010, Single Fellow}, issn = {1530-6992}, url = {http://dx.doi.org/10.1021/nl101105j}, author = {Ropp, Chad and Probst, Roland and Cummins, Zachary and Kumar, Rakesh and Berglund, Andrew J and Raghavan, Srinivasa R and Edo Waks and Shapiro, Benjamin} } @article {Carr2010, title = {Mesoscopic effects in quantum phases of ultracold quantum gases in optical lattices}, journal = {Phys. Rev. A}, volume = {81}, number = {1}, year = {2010}, month = {jan}, keywords = {2010, Single Fellow}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v81/i1/e013613}, author = {L D Carr and Wall, M. L. and Schirmer, D. G. and Roger C Brown and James E Williams and Charles W Clark} } @article {2418, title = {Non-Abelian quantum order in spin-orbit-coupled semiconductors: Search for topological Majorana particles in solid-state systems}, journal = {Phys. Rev. B}, volume = {82}, year = {2010}, month = {12/2010}, pages = {214509}, doi = {10.1103/PhysRevB.82.214509}, author = {Jay D Sau and Tewari, Sumanta and Roman M Lutchyn and Tudor D Stanescu and S. Das Sarma} } @article {Ghosh2010, title = {Non-Abelian topological order in noncentrosymmetric superconductors with broken time-reversal symmetry}, journal = {Phys. Rev. B}, volume = {82}, number = {18}, year = {2010}, month = {nov}, keywords = {2010, Single Fellow}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v82/i18/e184525}, author = {Ghosh, Parag and Jay D Sau and Tewari, Sumanta and S. Das Sarma} } @article { ISI:000275060000055, title = {Observation of Elastic Doublon Decay in the Fermi-Hubbard Model}, journal = {PHYSICAL REVIEW LETTERS}, volume = {104}, number = {8}, year = {2010}, month = {FEB 26}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.104.080401}, author = {Strohmaier, Niels and Greif, Daniel and Jordens, Robert and Tarruell, Leticia and Moritz, Henning and Esslinger, Tilman and Sensarma, Rajdeep and Pekker, David and Altman, Ehud and Demler, Eugene} } @article {Jimenez-Garcia2010, title = {Phases of a Two-Dimensional Bose Gas in an Optical Lattice}, journal = {Phys. Rev. Lett.}, volume = {105}, number = {11}, year = {2010}, month = {sep}, pages = {110401}, keywords = {2010, Multiple Fellows}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v105/i11/e110401}, author = {Karina Jim{\'e}nez-Garc{\'\i}a and R L Compton and Y -J Lin and William D Phillips and J V Porto and Ian B Spielman} } @article {Soderberg2010, title = {Phonon-mediated entanglement for trapped ion quantum computing}, journal = {Rep. Prog. Phys.}, volume = {73}, number = {3}, year = {2010}, month = {mar}, pages = {036401}, abstract = {Trapped ions are a near ideal system to study quantum information processing due to the high degree of control over the ion{\textquoteright}s external confinement and internal degrees of freedom. We demonstrate the key steps necessary for trapped ion quantum computing and focus on phonon-mediated entangling gates. We highlight several key algorithms implemented over the last decade with these gates and give a detailed description of Grover{\textquoteright}s quantum database search implemented with two trapped ion qubits.}, keywords = {2010}, issn = {0034-4885}, url = {http://stacks.iop.org/0034-4885/73/i=3/a=036401}, author = {Soderberg, K-A Brickman and Christopher Monroe} } @article { ISI:000283771500009, title = {Plasmon-phonon coupling in graphene}, journal = {PHYSICAL REVIEW B}, volume = {82}, number = {19}, year = {2010}, month = {NOV 3}, issn = {1098-0121}, doi = {10.1103/PhysRevB.82.195406}, author = {Hwang, E. H. and Sensarma, Rajdeep and S. Das Sarma} } @article {Ropp2010a, title = {Positioning and immobilization of individual quantum dots with nanoscale precision}, journal = {Nano Lett.}, volume = {10}, number = {11}, year = {2010}, month = {nov}, pages = {4673{\textendash}9}, publisher = {American Chemical Society}, abstract = {We demonstrate a technique for the precise immobilization of nanoscale objects at accurate positions on two-dimensional surfaces. We have developed a water-based photoresist that causes nanostructures such as colloidal quantum dots to segregate to a thin layer at surfaces. By combining this material with electroosmotic feedback control, we demonstrate the ability to position selected, individual quantum dots at specific locations and to immobilize them with 130 nm precision via localized UV exposure.

}, keywords = {2010, Adhesiveness, Electroplating, Electroplating: methods, Materials Testing, Micromanipulation, Micromanipulation: methods, Quantum Dots, Single Fellow, Surface Properties, Ultraviolet Rays}, issn = {1530-6992}, url = {http://dx.doi.org/10.1021/nl1029557}, author = {Ropp, Chad and Cummins, Zachary and Probst, Roland and Qin, Sijia and John T Fourkas and Shapiro, Benjamin and Edo Waks} } @article {Sheng2010, title = {Preliminary studies for anapole moment measurements in rubidium and francium}, journal = {J. Phys. B: At. Mol. Opt. Phys.}, volume = {43}, number = {7}, year = {2010}, month = {apr}, pages = {074004}, abstract = {Preparations for the anapole measurement in Fr indicate the possibility of performing a similar measurement in a chain of Rb. The sensitivity analysis based on a single-nucleon model shows the potential for placing strong limits on the nucleon weak interaction parameters. There are values of the magnetic fields at much lower values than previously found that are insensitive to first-order changes in the field. The anapole moment effect in Rb corresponds to an equivalent electric field that is 80 times smaller than in Fr, but the stability of the isotopes and the current performance of the dipole trap in the apparatus presented here are encouraging for pursuing the measurement.}, keywords = {2010}, issn = {0953-4075}, url = {http://stacks.iop.org/0953-4075/43/i=7/a=074004}, author = {Dong Sheng and Luis A Orozco and Gomez, E.} } @article {Stanescu2010, title = {Proximity effect at the superconductor{\textendash}topological insulator interface}, journal = {Phys. Rev. B}, volume = {81}, number = {24}, year = {2010}, month = {jun}, keywords = {2010, Single Fellow}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v81/i24/e241310}, author = {Tudor D Stanescu and Jay D Sau and Roman M Lutchyn and S. Das Sarma} } @article {2550, title = {Realistic Time-Reversal Invariant Topological Insulators with Neutral Atoms}, journal = {PHYSICAL REVIEW LETTERS}, volume = {105}, year = {2010}, month = {DEC 16}, pages = {255302}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.105.255302}, author = {N. Goldman and Satija, I. and Nikolic, P. and Bermudez, A. and Martin-Delgado, M. A. and Lewenstein, M. and Ian B Spielman} } @article {Levine2010a, title = {RECIST versus volume measurement in medical CT using ellipsoids of known size}, journal = {Optics Express}, volume = {18}, number = {8}, year = {2010}, month = {apr}, pages = {8151}, publisher = {OSA}, abstract = {Two hundred eighty three uniaxial ellipsoids with sizes from 4 mm to 11 mm were measured with a coordinate measuring matching (CMM) and also scanned using a medical computed tomography (CT) machine. Their volumes were determined by counting voxels over a threshold, as well as using equivalent volumes from the length given by the RECIST 1.1 criterion (Response Evaluation Criteria in Solid Tumors). The volumetric measurements yield an order of magnitude reduction in residuals compared to the CMM measurements than the residuals of the RECIST measurements also compared to the CMM measurements.}, keywords = {2010, Medical optics instrumentation, X-ray imaging}, issn = {1094-4087}, url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-18-8-8151}, author = {Zachary H Levine and Borchardt, Bruce R. and Brandenburg, Nolan J. and Charles W Clark and Muralikrishnan, Bala and Shakarji, Craig M. and Chen, Joseph J. and Siegel, Eliot L.} } @article {Metcalfe2010, title = {Resolved Sideband Emission of InAs/GaAs Quantum Dots Strained by Surface Acoustic Waves}, journal = {Phys. Rev. Lett.}, volume = {105}, number = {3}, year = {2010}, month = {jul}, keywords = {2010, Multiple JQI Affil., Single Fellow}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v105/i3/e037401}, author = {Michael Metcalfe and Carr, S. and Andreas Muller and Glenn S Solomon and John R Lawall} } @article {Sridharan2010, title = {Reversible tuning of photonic crystal cavities using photochromic thin films}, journal = {Appl. Phys. Lett.}, volume = {96}, number = {15}, year = {2010}, month = {apr}, pages = {153303}, keywords = {2010, CMAMO, integrated optics, Multiple Fellows, nanophotonics, optical films, optical polymers, optical tuning, organic compounds, photochemistry, photochromism, photonic crystals, red shift}, issn = {00036951}, url = {http://link.aip.org/link/?APPLAB/96/153303/1}, author = {Deepak Sridharan and Edo Waks and Glenn S Solomon and John T Fourkas} } @article {Sau2010, title = {Robustness of Majorana fermions in proximity-induced superconductors}, journal = {Phys. Rev. B}, volume = {82}, number = {9}, year = {2010}, month = {sep}, pages = {094522}, keywords = {2010, Single Fellow}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v82/i9/e094522}, author = {Jay D Sau and Roman M Lutchyn and Tewari, Sumanta and S. Das Sarma} } @article {Bell2010, title = {A slow atom source using a collimated effusive oven and a single-layer variable pitch coil Zeeman slower}, journal = {Rev. Sci. Instrum.}, volume = {81}, number = {1}, year = {2010}, month = {jan}, pages = {013105}, abstract = {We describe a simple slow atom source for loading a rubidium magneto-optical trap. The source includes an effusive oven with a long heated collimation tube. Almost all components are standard vacuum parts. The heating elements and thermocouples are external to the vacuum, protecting them from the hostile hot alkali environment and allowing repair without breaking vacuum. The thermal source is followed by a Zeeman slower with a single-layer coil of variable winding pitch. The single-layer design is simple to construct and has low inductance which allows for rapid switching of the magnetic field. The coil pitch was determined by fitting the analytic form of the magnetic field for a variable winding pitch to the desired magnetic field profile required to slow atoms. The measured magnetic field for the constructed coil is in excellent agreement with the desired field. The source produces atoms at 35 m/s with a flux up to 2 x 10(10) cm(-2) s(-1) at 200 degrees C.}, keywords = {2010, magnetic fields, magnetic traps, magneto-optical effects, rubidium, thermocouples}, issn = {1089-7623}, url = {http://link.aip.org/link/?RSINAK/81/013105/1}, author = {Bell, S. C. and Junker, M. and Jasperse, M. and L D Turner and Y -J Lin and Ian B Spielman and Scholten, R. E.} } @article { ISI:000281280100001, title = {Spin squeezing of high-spin, spatially extended quantum fields}, journal = {NEW JOURNAL OF PHYSICS}, volume = {12}, year = {2010}, month = {AUG 25}, issn = {1367-2630}, doi = {10.1088/1367-2630/12/8/085011}, author = {Sau, Jay D. and Leslie, Sabrina R. and Cohen, Marvin L. and Stamper-Kurn, Dan M.} } @article { ISI:000275543500039, title = {Spin-Charge Interplay in Electronic Liquid Crystals: Fluctuating Spin Stripe Driven by Charge Nematic Ordering}, journal = {PHYSICAL REVIEW LETTERS}, volume = {104}, number = {10}, year = {2010}, month = {MAR 12}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.104.106405}, author = {Sun, Kai and Lawler, Michael J. and Kim, Eun-Ah} } @article {Sun2010, title = {Spontaneous inhomogeneous phases in ultracold dipolar Fermi gases}, journal = {Phys. Rev. B}, volume = {82}, number = {7}, year = {2010}, month = {aug}, keywords = {2010, Single Fellow}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v82/i7/e075105}, author = {Kai Sun and Wu, Congjun and S. Das Sarma} } @article {Cheng2010a, title = {Stable topological superconductivity in a family of two-dimensional fermion models}, journal = {Phys. Rev. B}, volume = {81}, number = {2}, year = {2010}, month = {jan}, keywords = {2010, Multiple Fellows}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v81/i2/e024504}, author = {Cheng, Meng and Kai Sun and Victor M Galitski and S. Das Sarma} } @article {Arora2010, title = {State-insensitive bichromatic optical trapping}, journal = {Phys. Rev. A}, volume = {82}, number = {2}, year = {2010}, month = {aug}, keywords = {2010, Multiple JQI Affil., Single Fellow}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v82/i2/e022509}, author = {Arora, Bindiya and Marianna S Safronova and Charles W Clark} } @article { ISI:000281658500003, title = {Subband engineering even-denominator quantum Hall states}, journal = {PHYSICAL REVIEW B}, volume = {82}, number = {12}, year = {2010}, month = {SEP 9}, issn = {2469-9950}, doi = {10.1103/PhysRevB.82.121304}, author = {Scarola, V. W. and May, C. and Peterson, M. R. and Troyer, M.} } @article {ISI:000273947200008, title = {A theorem for the existence of Majorana fermion modes in spin{\textendash}orbit-coupled semiconductors}, journal = {Annals of Physics}, volume = {325}, number = {1, Sp. Iss. SI}, year = {2010}, month = {jan}, pages = {219{\textendash}231}, abstract = {We prove an index theorem for the existence of Majorana zero modes in a semiconducting thin film with a sizable spin{\textendash}orbit coupling when it is adjacent to an s-wave superconductor. The theorem, which is analogous to the Jackiw{\textendash}Rebbi index theorem for the zero modes in mass domain walls in one-dimensional Dirac theory, applies to vortices with odd flux-quantum in a semiconducting film in which s-wave superconductivity and a Zeeman splitting are induced by proximity effect. The momentum space construction of the zero-mode solution presented here is complementary to the approximate real space solution of the Bogoliubov-de Gennes equations at a vortex core (Sau et al., arXiv:0907.2239 [17]), proving the existence of non-degenerate zero-energy Majorana excitations and the resultant non-Abelian topological order in the semiconductor heterostructure. With increasing magnitude of the proximity-induced pairing potential, the non-Abelian superconducting state makes a topological quantum phase transition to an ordinary s-wave superconducting state which no topological order.

}, keywords = {2010, majorana fermions, non-abelian statistics, semiconductor, superconductor, topological quantum computation}, issn = {0003-4916}, url = {http://dx.doi.org/10.1016/j.aop.2009.11.003}, author = {Tewari, Sumanta and Jay D Sau and S. Das Sarma} } @article {Mitroy2010, title = {Theory and applications of atomic and ionic polarizabilities}, journal = {J. Phys. B: At. Mol. Opt. Phys.}, volume = {43}, number = {20}, year = {2010}, month = {oct}, pages = {202001}, abstract = {Atomic polarization phenomena impinge upon a number of areas and processes in physics. The dielectric constant and refractive index of any gas are examples of macroscopic properties that are largely determined by the dipole polarizability. When it comes to microscopic phenomena, the existence of alkaline-earth anions and the recently discovered ability of positrons to bind to many atoms are predominantly due to the polarization interaction. An imperfect knowledge of atomic polarizabilities is presently looming as the largest source of uncertainty in the new generation of optical frequency standards. Accurate polarizabilities for the group I and II atoms and ions of the periodic table have recently become available by a variety of techniques. These include refined many-body perturbation theory and coupled-cluster calculations sometimes combined with precise experimental data for selected transitions, microwave spectroscopy of Rydberg atoms and ions, refractive index measurements in microwave cavities, ab initio calculations of atomic structures using explicitly correlated wavefunctions, interferometry with atom beams and velocity changes of laser cooled atoms induced by an electric field. This review examines existing theoretical methods of determining atomic and ionic polarizabilities, and discusses their relevance to various applications with particular emphasis on cold-atom physics and the metrology of atomic frequency standards.}, keywords = {2010, Multiple JQI Affil., Single Fellow}, issn = {0953-4075}, url = {http://stacks.iop.org/0953-4075/43/i=20/a=202001}, author = {Mitroy, J and Marianna S Safronova and Charles W Clark} } @article {Dzero2010, title = {Topological Kondo Insulators}, journal = {Phys. Rev. Lett.}, volume = {104}, number = {10}, year = {2010}, month = {mar}, keywords = {2010, Single Fellow}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v104/i10/e106408}, author = {Maxim Dzero and Kai Sun and Victor M Galitski and Coleman, Piers} } @article { ISI:000277007700034, title = {Topological Phases of Dipolar Particles in Elongated Wannier Orbitals}, journal = {PHYSICAL REVIEW LETTERS}, volume = {104}, number = {16}, year = {2010}, month = {APR 23}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.104.165303}, author = {Sun, Kai and Zhao, Erhai and Liu, W. Vincent} } @article {Stanescu2010a, title = {Topological states in two-dimensional optical lattices}, journal = {Phys. Rev. A}, volume = {82}, number = {1}, year = {2010}, month = {jul}, keywords = {2010, Multiple Fellows}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v82/i1/e013608}, author = {Tudor D Stanescu and Victor M Galitski and S. Das Sarma} } @article { ISI:000286342900008, title = {Two-dimensional surface charge transport in topological insulators}, journal = {PHYSICAL REVIEW B}, volume = {82}, number = {15}, year = {2010}, month = {OCT 29}, issn = {1098-0121}, doi = {10.1103/PhysRevB.82.155457}, author = {Culcer, Dimitrie and Hwang, E. H. and Stanescu, Tudor D. and S. Das Sarma} } @article {Campbell2010, title = {Ultrafast Gates for Single Atomic Qubits}, journal = {Phys. Rev. Lett.}, volume = {105}, number = {9}, year = {2010}, month = {aug}, pages = {090502}, abstract = {We demonstrate the use of an optical frequency comb to coherently control and entangle atomic qubits. A train of off-resonant ultrafast laser pulses is used to efficiently and coherently transfer population between electronic and vibrational states of trapped atomic ions and implement an entangling quantum logic gate with high fidelity. This technique can be extended to the high field regime where operations can be performed faster than the trap frequency. This general approach can be applied to more complex quantum systems, such as large collections of interacting atoms or molecules.

}, keywords = {2010, Single Fellow}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v105/i9/e090502}, author = {W C Campbell and J Mizrahi and Q Quraishi and Crystal Senko and David Hayes and D Hucul and D N Matsukevich and P Maunz and Christopher Monroe and Steven Olmschenk} } @article {Muller2010, title = {Ultrahigh-finesse, low-mode-volume Fabry{\textendash}Perot microcavity}, journal = {Optics Letters}, volume = {35}, number = {13}, year = {2010}, month = {jun}, pages = {2293}, publisher = {OSA}, abstract = {Ultralow-loss concave micromirrors with radius of curvature below 60$Î¼$m were fabricated by laser ablation and reflective coatings. A 10-$Î¼$m-long microcavity with a mode volume of 40$Î¼$m3 was set up with two such mirrors, and the cavity linewidth was measured both spectrally and temporally. The smallest linewidth obtained was 96MHz, corresponding to a quality factor of 3.3{\texttimes}106 and a finesse in excess of 1.5{\texttimes}105. With these parameters, we estimate that a variety of solid-state quantum emitters coupled to the cavity may enter the strong coupling regime.}, keywords = {2010, Fabry-Perot, Multiple JQI Affil., Quantum optics, Single Fellow}, issn = {0146-9592}, url = {http://ol.osa.org/abstract.cfm?URI=ol-35-13-2293}, author = {Andreas Muller and Flagg, Edward B. and John R Lawall and Glenn S Solomon} } @article {Sau2010a, title = {Universal quantum computation in a semiconductor quantum wire network}, journal = {Phys. Rev. A}, volume = {82}, number = {5}, year = {2010}, month = {nov}, keywords = {2010, Single Fellow}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v82/i5/e052322}, author = {Jay D Sau and Tewari, Sumanta and S. Das Sarma} } @article {Kuo2009, title = {4{\textasciimacron}-quasi-phase-matched interactions in GaAs microdisk cavities}, journal = {Optics Letters}, volume = {34}, number = {22}, year = {2009}, month = {nov}, pages = {3580}, publisher = {OSA}, abstract = {We describe quasi-phase-matched nonlinear interactions in materials that possess 4{\textasciimacron} symmetry, such as GaAs. 4{\textasciimacron} symmetry together with curved propagation geometries produce quasi phase matching (QPM) without need of external domain inversions. To improve efficiency of nonlinear optical mixing, 4{\textasciimacron}-QPM can be combined with resonant microcavities such as whispering-gallery-mode microdisks. All interacting waves must be resonant with the cavity, which leads to stringent tuning requirements. We show tuning behavior for second-harmonic generation in a GaAs microdisk cavity and estimate that, with milliwatt-level external pumping, approximately 0.1\% power-conversion efficiency can be obtained with negligible higher-order nonlinear effects.

}, keywords = {2009, Harmonic generation and mixing, Semiconductor materials, Semiconductor nonlinear optics including MQW, Single Fellow}, issn = {0146-9592}, url = {http://ol.osa.org/abstract.cfm?URI=ol-34-22-3580}, author = {Paulina S Kuo and Wei Fang and Glenn S Solomon} } @conference {Safronova2009, title = {Blackbody radiation shifts and theoretical contributions to atomic clock research}, booktitle = {2009 IEEE International Frequency Control Symposium Joint with the 22nd European Frequency and Time forum}, year = {2009}, month = {apr}, pages = {132{\textendash}140}, publisher = {IEEE}, organization = {IEEE}, abstract = {A review of the theoretical calculations of the blackbody radiation (BBR) shifts in various systems of interest to the atomic clock research in presented. The calculations for monovalent systems, such as Ca+, Sr+, and Rb are carried out using the relativistic all-order single-double method where all single and double excitations of the Dirac-Fock wave function are included to all orders of perturbation theory. New method for accurate calculations of BBR shifts for divalent systems such as Sr is discussed. The new approach combines the relativistic all-order method and the configuration interaction method. The evaluation of the uncertainty of the BBR shift values is discussed in detail.}, keywords = {2009}, url = {http://ieeexplore.ieee.org/xpl/freeabs\_all.jsp?arnumber=5168156}, author = {Marianna S Safronova and Mikhail G Kozlov and Jiang, Dansha and Arora, Bindiya and Charles W Clark and U I Safronova and Johnsonk, W. R.} } @article {Jiang2009, title = {Blackbody-radiation shift in a 88 Sr + ion optical frequency standard}, journal = {J. Phys. B: At. Mol. Opt. Phys.}, volume = {42}, number = {15}, year = {2009}, month = {aug}, pages = {154020}, abstract = {{The blackbody-radiation (BBR) shift of the 5s{\textendash}4d 5/2 clock transition in 88 Sr + is calculated to be 0.250(9) Hz at room temperature}, keywords = {2009}, issn = {0953-4075}, url = {http://stacks.iop.org/0953-4075/42/i=15/a=154020}, author = {Jiang, Dansha and Arora, Bindiya and Marianna S Safronova and Charles W Clark} } @article {Lin2009c, title = {Bose-Einstein Condensate in a Uniform Light-Induced Vector Potential}, journal = {Phys. Rev. Lett.}, volume = {102}, number = {13}, year = {2009}, month = {mar}, pages = {130401}, keywords = {2009, Multiple Fellows}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v102/i13/e130401}, author = {Y -J Lin and R L Compton and Abigail R Perry and William D Phillips and J V Porto and Ian B Spielman} } @article {Muller2009a, title = {Coupling an epitaxial quantum dot to a fiber-based external-mirror microcavity}, journal = {Appl. Phys. Lett.}, volume = {95}, number = {17}, year = {2009}, month = {oct}, pages = {173101}, keywords = {2009, distributed Bragg reflectors, gallium arsenide, microcavity lasers, Multiple JQI Affil., quantum dot lasers, Single Fellow}, issn = {00036951}, url = {http://link.aip.org/link/?APPLAB/95/173101/1}, author = {Andreas Muller and Flagg, Edward B. and Michael Metcalfe and John R Lawall and Glenn S Solomon} } @article {Muller2009, title = {Creating Polarization-Entangled Photon Pairs from a Semiconductor Quantum Dot Using the Optical Stark Effect}, journal = {Phys. Rev. Lett.}, volume = {103}, number = {21}, year = {2009}, month = {nov}, keywords = {2009, Multiple JQI Affil., Single Fellow}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v103/i21/e217402}, author = {Andreas Muller and Wei Fang and John R Lawall and Glenn S Solomon} } @article {Leibrandt2009, title = {Demonstration of a scalable, multiplexed ion trap for quantum information processing}, year = {2009}, month = {apr}, pages = {18}, abstract = {A scalable, multiplexed ion trap for quantum information processing is fabricated and tested. The trap design and fabrication process are optimized for scalability to small trap size and large numbers of interconnected traps, and for integration of control electronics and optics. Multiple traps with similar designs are tested with Cd+, Mg+, and Sr+ ions at room temperature and with Sr+ at 6 K, with respective ion lifetimes of 90 s, 300 +/- 30 s, 56 +/- 6 s, and 4.5 +/- 1.1 hours. The motional heating rate for Mg+ at room temperature and a trap frequency of 1.6 MHz is measured to be 7 +/- 3 quanta per millisecond. For Sr+ at 6 K and 540 kHz the heating rate is measured to be 220 +/- 30 quanta per second.}, keywords = {2009}, url = {http://arxiv.org/abs/0904.2599}, author = {Leibrandt, D. R. and Labaziewicz, J. and R J Clark and Chuang, I. L. and Epstein, R. J. and Ospelkaus, C. and Wesenberg, J. H. and Bollinger, J. J. and Leibfried, D. and David J Wineland and Stick, D. and J D Sterk and Christopher Monroe and Pai, C. -S. and Low, Y. and Frahm, R. and Slusher, R. E.} } @article {Sun2009, title = {Detection of a single-charge defect in a metal-oxide-semiconductor structure using vertically coupled Al and Si single-electron transistors}, journal = {Phys. Rev. B}, volume = {80}, number = {15}, year = {2009}, month = {oct}, pages = {5}, abstract = {An Al-AlO\_x-Al single-electron transistor (SET) acting as the gate of a narrow (\~{} 100 nm) metal-oxide-semiconductor field-effect transistor (MOSFET) can induce a vertically aligned Si SET at the Si/SiO\_2 interface near the MOSFET channel conductance threshold. By using such a vertically coupled Al and Si SET system, we have detected a single-charge defect which is tunnel-coupled to the Si SET. By solving a simple electrostatic model, the fractions of each coupling capacitance associated with the defect are extracted. The results reveal that the defect is not a large puddle or metal island, but its size is rather small, corresponding to a sphere with a radius less than 1 nm. The small size of the defect suggests it is most likely a single-charge trap at the Si/SiO\_2 interface. Based on the ratios of the coupling capacitances, the interface trap is estimated to be about 20 nm away from the Si SET.

}, keywords = {2009, Single Fellow}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v80/i15/e153310 http://arxiv.org/abs/0908.2479}, author = {Luyan Sun and B E Kane} } @article {2465, title = {Field-sensitive addressing and control of field-insensitive neutral-atom qubits}, journal = {Nature Physics}, volume = {5}, year = {2009}, month = {7/2009}, pages = {575-580}, doi = {10.1038/nphys1330}, author = {Lundblad, N. and J. M. Obrecht and Ian B Spielman and J V Porto} } @article { ISI:000263389500057, title = {Giant Nernst Effect due to Fluctuating Cooper Pairs in Superconductors}, journal = {PHYSICAL REVIEW LETTERS}, volume = {102}, number = {6}, year = {2009}, month = {FEB 13}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.102.067001}, author = {Serbyn, M. N. and Skvortsov, M. A. and Varlamov, A. A. and Victor M Galitski} } @article {G.Brida2009, title = {Improved implementation and modeling of deadtime reduction in an actively multiplexed detection system}, journal = {Journal of Modern Optics}, volume = {56}, year = {2009}, pages = {405{\textendash}412}, keywords = {2009}, author = {Giorgio Brida and Ivo P Degiovanni and Valentina Schettini and Sergey V Polyakov and Alan L Migdall} } @article {Brida2009a, title = {Improved implementation of the Alicki{\textendash}Van Ryn nonclassicality test for a single particle using Si detectors}, journal = {Phys. Rev. A}, volume = {79}, number = {4}, year = {2009}, month = {apr}, keywords = {2009}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v79/i4/e044102}, author = {Giorgio Brida and Ivo P Degiovanni and Marco Genovese and Fabrizio Piacentini and Valentina Schettini and Gisin, Nicolas and Sergey V Polyakov and Alan L Migdall} } @article { ISI:000264768900043, title = {Mott transition on a triangular lattice}, journal = {PHYSICAL REVIEW B}, volume = {79}, number = {11}, year = {2009}, month = {MAR}, issn = {1098-0121}, doi = {10.1103/PhysRevB.79.115116}, author = {Galanakis, Dimitrios and Stanescu, Tudor D. and Phillips, Philip} } @article {Galitski2009, title = {Paired electron pockets in the hole-doped cuprates}, journal = {Phys. Rev. B}, volume = {79}, number = {13}, year = {2009}, month = {apr}, keywords = {2009, Single Fellow}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v79/i13/e134512}, author = {Victor M Galitski and Sachdev, Subir} } @article {Balakrishnan2009, title = {Particle-Hole Asymmetry and Brightening of Solitons in a Strongly Repulsive Bose-Einstein Condensate}, journal = {Phys. Rev. Lett.}, volume = {103}, number = {23}, year = {2009}, month = {12/2009}, keywords = {2009}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.103.230403}, author = {Balakrishnan, Radha and Indubala Satija and Charles W Clark} } @article {Mintert2009, title = {Phase transitions, entanglement and quantum noise interferometry in cold atoms}, journal = {EPL}, volume = {86}, number = {1}, year = {2009}, month = {apr}, pages = {17003}, abstract = {We show that entanglement monotones reveal the pronounced enhancement of entanglement at a quantum phase transition, when they are sensitive to long-range high-order correlations. Such monotones are found to develop a sharp interferometric peak at the critical point, and to exhibit universal scaling. We demonstrate that similar features are shared by noise correlation spectra, and verify that these experimentally accessible quantities encode entanglement information and probe separability. We give a prescription, for mesoscopic scale systems of how to extract the pronounced enhancement of entanglement at a quantum phase transition from limited accessible experimental data.}, keywords = {2009}, issn = {0295-5075}, url = {http://stacks.iop.org/0295-5075/86/i=1/a=17003}, author = {Mintert, F. and A M Rey and Indubala Satija and Charles W Clark} } @article { ISI:000269639300015, title = {Physical mechanisms of interface-mediated intervalley coupling in Si}, journal = {PHYSICAL REVIEW B}, volume = {80}, number = {8}, year = {2009}, month = {AUG}, issn = {1098-0121}, doi = {10.1103/PhysRevB.80.081305}, author = {Saraiva, A. L. and Calderon, M. J. and Hu, Xuedong and S. Das Sarma and Koiller, Belita} } @article {Elberson2009, title = {A picosecond time-resolved electron energy spectrometer based on Cerenkov radiation}, journal = {Rev. Sci. Instrum.}, volume = {80}, number = {2}, year = {2009}, month = {feb}, pages = {023302}, abstract = {The energy spectrum of relativistic electrons is an important characterization of high intensity laser-matter interactions. We present a technique that utilizes Cerenkov radiation to measure the time-resolved energy distribution of electrons. Electrons escaping from targets irradiated by high-intensity laser pulses were measured, demonstrating the feasibility of such a novel diagnostic. Limitations on the time resolution of this diagnostic are also discussed.}, keywords = {2009, Cherenkov counters, electron spectrometers, relativistic electron beams}, issn = {1089-7623}, url = {http://link.aip.org/link/?RSINAK/80/023302/1}, author = {Lee N Elberson and Ping, Yuan and Shepherd, Ronnie L and Patel, Pravesh K and Mackinnon, Andrew J and Wendell T Hill III} } @article {Campbell2009, title = {Probing interactions between ultracold fermions}, journal = {Science}, volume = {324}, number = {5925}, year = {2009}, month = {apr}, pages = {360{\textendash}3}, abstract = {At ultracold temperatures, the Pauli exclusion principle suppresses collisions between identical fermions. This has motivated the development of atomic clocks with fermionic isotopes. However, by probing an optical clock transition with thousands of lattice-confined, ultracold fermionic strontium atoms, we observed density-dependent collisional frequency shifts. These collision effects were measured systematically and are supported by a theoretical description attributing them to inhomogeneities in the probe excitation process that render the atoms distinguishable. This work also yields insights for zeroing the clock density shift.

}, keywords = {2009}, issn = {1095-9203}, url = {http://www.sciencemag.org/content/324/5925/360.abstract}, author = {Gretchen K Campbell and Boyd, M. M. and J W Thomsen and Martin, M J and Blatt, S and Swallows, M D and T L Nicholson and Fortier, T and Oates, C W and Diddams, S A and Lemke, N D and Pascal Naidon and Paul S Julienne and Jun Ye and Ludlow, A. D.} } @article {Luo2009, title = {Protocols and techniques for a scalable atom-photon quantum network}, journal = {Fortschritte der Physik}, volume = {57}, number = {11-12}, year = {2009}, month = {sep}, pages = {1133{\textendash}1152}, keywords = {2009, Single Fellow}, issn = {00158208}, url = {http://doi.wiley.com/10.1002/prop.200900093}, author = {L Luo and David Hayes and T A Manning and D N Matsukevich and P Maunz and Steven Olmschenk and J D Sterk and Christopher Monroe} } @article {Huckans2009, title = {Quantum and Classical Dynamics of a BEC in a Large-Period Optical Lattice}, journal = {Physical Review A}, volume = {80}, year = {2009}, month = {jan}, pages = {043609}, abstract = {We experimentally investigate diffraction of a Rb-87 Bose-Einstein condensate from a 1D optical lattice. We use a range of lattice periods and timescales, including those beyond the Raman-Nath limit. We compare the results to quantum mechanical and classical simulations, with quantitative and qualitative agreement, respectively. The classical simulation predicts that the envelope of the time-evolving diffraction pattern is shaped by caustics: singularities in the phase space density of classical trajectories. This behavior becomes increasingly clear as the lattice period grows.

}, keywords = {2009}, url = {http://arxiv.org/abs/0901.1386}, author = {J H Huckans and Ian B Spielman and Tolra, B. Laburthe and William D Phillips and J V Porto} } @article { ISI:000267599600011, title = {Quantum control and manipulation of donor electrons in Si-based quantum computing}, journal = {JOURNAL OF APPLIED PHYSICS}, volume = {105}, number = {12}, year = {2009}, note = {29th International Conference on Physics of Semiconductors, Rio de Janeiro, BRAZIL, JUL 27-AUG 01, 2008}, month = {JUN 15}, issn = {0021-8979}, doi = {10.1063/1.3124084}, author = {Calderon, M. J. and Saraiva, A. and Koiller, Belita and S. Das Sarma} } @article {Idziaszek2009, title = {Quantum theory of ultracold atom-ion collisions}, journal = {Phys. Rev. A}, volume = {79}, number = {1}, year = {2009}, month = {jan}, keywords = {2009}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v79/i1/e010702}, author = {Idziaszek, Zbigniew and Tommaso Calarco and Paul S Julienne and Simoni, Andrea} } @article {Spielman2009, title = {Raman processes and effective gauge potentials}, journal = {Phys. Rev. A}, volume = {79}, number = {6}, year = {2009}, month = {jun}, pages = {063613}, keywords = {2009, Single Fellow}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v79/i6/e063613}, author = {Ian B Spielman} } @article {Lin2009a, title = {Rapid production of R87b Bose-Einstein condensates in a combined magnetic and optical potential}, journal = {Phys. Rev. A}, volume = {79}, number = {6}, year = {2009}, month = {jun}, pages = {063631}, keywords = {2009}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v79/i6/e063631}, author = {Y -J Lin and Abigail R Perry and R L Compton and Ian B Spielman and J V Porto} } @article { ISI:000270383200044, title = {Robust pairing mechanism from repulsive interactions}, journal = {PHYSICAL REVIEW B}, volume = {80}, number = {11}, year = {2009}, month = {SEP}, issn = {1098-0121}, doi = {10.1103/PhysRevB.80.115116}, author = {Al-Hassanieh, K. A. and Batista, C. D. and Sengupta, P. and Feiguin, A. E.} } @article {Brida2009, title = {Scalable multiplexed detector system for high-rate telecom-band single-photon detection}, journal = {Rev. Sci. Instrum.}, volume = {80}, number = {11}, year = {2009}, month = {nov}, pages = {116103}, abstract = {We present an actively multiplexed photon-counting detection system at telecom wavelengths that overcomes the difficulties of photon-counting at high rates. We find that for gated detectors, the heretofore unconsidered deadtime associated with the detector gate is a critical parameter, that limits the overall scalability of the scheme to just a few detectors. We propose and implement a new scheme that overcomes this problem and restores full scalability that allows an order of magnitude improvement with systems with as few as 4 detectors. When using just two multiplexed detectors, our experimental results show a 5x improvement over a single detector and a greater than 2x improvement over multiplexed schemes that do not consider gate deadtime.}, keywords = {2009, infrared detectors, multiplexing, optical receivers, photodetectors, Photon counting, quantum communication, Quantum optics}, issn = {1089-7623}, url = {http://link.aip.org/link/?RSINAK/80/116103/1}, author = {Giorgio Brida and Ivo P Degiovanni and Fabrizio Piacentini and Valentina Schettini and Sergey V Polyakov and Alan L Migdall} } @article {2461, title = {State diagrams for harmonically trapped bosons in optical lattices}, journal = {Phys. Rev. A}, volume = {79}, year = {2009}, month = {5/2009}, pages = {053605}, doi = {10.1103/PhysRevA.79.053605}, author = {Rigol, Marcos and George G. Batrouni and Valery G. Rousseau and Richard T. Scalettar} } @article {Mitra2009, title = {Superfluid and Fermi-liquid phases of Bose-Fermi mixtures in optical lattices}, journal = {Phys. Rev. A}, volume = {79}, number = {5}, year = {2009}, month = {may}, keywords = {2009}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v79/i5/e055601}, author = {Kaushik Mitra and Carl J Williams and C A R S{\'a} de Melo} } @article {Satija2009, title = {Symmetry-breaking and symmetry-restoring dynamics of a mixture of Bose-Einstein condensates in a double well}, journal = {Phys. Rev. A}, volume = {79}, number = {3}, year = {2009}, month = {mar}, pages = {033616}, abstract = {We study the coherent nonlinear tunneling dynamics of a binary mixture of Bose-Einstein condensates in a double-well potential. We demonstrate the existence of a new type of mode associated with the "swapping" of the two species in the two wells of the potential. In contrast to the symmetry breaking macroscopic quantum self-trapping (MQST) solutions, the swapping modes correspond to the tunneling dynamics that preserves the symmetry of the double well potential. As a consequence of two distinct types of broken symmetry MQST phases where the two species localize in the different potential welils or coexist in the same well, the corresponding symmetry restoring swapping modes result in dynamics where the the two species either avoid or chase each other. In view of the possibility to control the interaction between the species, the binary mixture offers a very robust system to observe these novel effects as well as the phenomena of Josephson oscillations and pi-modes

}, keywords = {2009, Single Fellow}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v79/i3/e033616 }, author = {Indubala Satija and Balakrishnan, Radha and Naudus, Phillip and Heward, Jeffrey and Edwards, Mark and Charles W Clark} } @article {Lin2009b, title = {Synthetic magnetic fields for ultracold neutral atoms}, journal = {Nature}, volume = {462}, number = {7273}, year = {2009}, month = {dec}, pages = {628{\textendash}32}, publisher = {Macmillan Publishers Limited. All rights reserved}, abstract = {Neutral atomic Bose condensates and degenerate Fermi gases have been used to realize important many-body phenomena in their most simple and essential forms, without many of the complexities usually associated with material systems. However, the charge neutrality of these systems presents an apparent limitation-a wide range of intriguing phenomena arise from the Lorentz force for charged particles in a magnetic field, such as the fractional quantum Hall effect in two-dimensional electron systems. The limitation can be circumvented by exploiting the equivalence of the Lorentz force and the Coriolis force to create synthetic magnetic fields in rotating neutral systems. This was demonstrated by the appearance of quantized vortices in pioneering experiments on rotating quantum gases, a hallmark of superfluids or superconductors in a magnetic field. However, because of technical issues limiting the maximum rotation velocity, the metastable nature of the rotating state and the difficulty of applying stable rotating optical lattices, rotational approaches are not able to reach the large fields required for quantum Hall physics. Here we experimentally realize an optically synthesized magnetic field for ultracold neutral atoms, which is evident from the appearance of vortices in our Bose-Einstein condensate. Our approach uses a spatially dependent optical coupling between internal states of the atoms, yielding a Berry{\textquoteright}s phase sufficient to create large synthetic magnetic fields, and is not subject to the limitations of rotating systems. With a suitable lattice configuration, it should be possible to reach the quantum Hall regime, potentially enabling studies of topological quantum computation.

}, keywords = {2009, Multiple Fellows}, issn = {1476-4687}, url = {http://dx.doi.org/10.1038/nature08609}, author = {Y -J Lin and R L Compton and Karina Jim{\'e}nez-Garc{\'\i}a and J V Porto and Ian B Spielman} } @article {McFarland2009, title = {Temperature-dependent transport in a sixfold degenerate two-dimensional electron system on a H-Si(111) surface}, journal = {Phys. Rev. B}, volume = {80}, number = {16}, year = {2009}, month = {oct}, keywords = {2009, Single Fellow}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v80/i16/e161310}, author = {McFarland, Robert and Tomasz M Kott and Luyan Sun and Eng, K. and B E Kane} } @article {Stanescu2009, title = {Topological insulators and metals in atomic optical lattices}, journal = {Phys. Rev. A}, volume = {79}, number = {5}, year = {2009}, month = {may}, pages = {053639}, keywords = {2009, CMAMO, Multiple Fellows}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v79/i5/e053639}, author = {Tudor D Stanescu and Victor M Galitski and J Vaishnav and Charles W Clark and S. Das Sarma} } @article {Hormozi2009, title = {Topological Quantum Computing with Read-Rezayi States}, journal = {Phys. Rev. Lett.}, volume = {103}, number = {16}, year = {2009}, month = {oct}, keywords = {2009}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v103/i16/e160501}, author = {Hormozi, L. and Bonesteel, N. and Simon, S.} } @article {Kim2008, title = {Anomalous avoided level crossings in a Cooper-pair box spectrum}, journal = {Phys. Rev. B}, volume = {78}, number = {14}, year = {2008}, month = {oct}, abstract = {We have observed a few distinct anomalous avoided level crossings and voltage-dependent transitions in the excited-state spectrum of an Al/AlO(x)/Al Cooper-pair box (CPB). The device was measured at 40 mK in the 15-50 GHz frequency range. We find that a given level crosses the CPB spectrum at two different gate voltages; the frequency and splitting size of the two crossings differ and the splitting size depends on the Josephson energy of the CPB. We show that this behavior is not only consistent with the CPB being coupled to discrete charged "two-level" quantum systems, which move atomic distances in the CPB junctions, but that the spectra provide information about the fluctuators, which is not available from phase qubit spectra of anomalous avoided levels. In particular by fitting a model Hamiltonian to our data, we extract microscopic parameters for each fluctuator, including well asymmetry, tunneling amplitude, and the minimum hopping distance for each fluctuator. The tunneling rates range from less than 3.5-13 GHz, which represent values between 5 and 150\% of the well asymmetry, and the dipole moments give a minimum hopping distance of 0.3-0.8 A. We have also found that these discrete two-level systems have a pronounced effect on the relaxation time (T(1)) of the quantum states of the CPB and hence can be a source of dissipation for superconducting quantum bits.}, keywords = {2008, FLICKER 1/F NOISE, JOSEPHSON-JUNCTIONS, QUBIT, Single Fellow, SINGLE-ELECTRON TRANSISTORS, SMALL TUNNEL-JUNCTIONS}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v78/i14/e144506 http://apps.webofknowledge.com/full\_record.do?product=WOS\&search\_mode=GeneralSearch\&qid=2\&SID=3BoaAEpOPA@Jjha4jbH\&page=1\&doc=1}, author = {Kim, Z. and Zaretskey, V. and Yoon, Y. and J F Schneiderman and M D Shaw and P M Echternach and F C Wellstood and B S Palmer} } @article { ISI:000255237200053, title = {Anyonic braiding in optical lattices (vol 104, pg 18415, 2007)}, journal = {PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, volume = {105}, number = {15}, year = {2008}, month = {APR 15}, pages = {5945}, issn = {0027-8424}, doi = {10.1073/pnas.0802500105}, author = {Zhang, Chuanwei and Scarola, V. W. and Tewari, Sumanta and S. Das Sarma} } @article {Lundblad2008, title = {Atoms in a Radio-Frequency-Dressed Optical Lattice}, journal = {Phys. Rev. Lett.}, volume = {100}, number = {15}, year = {2008}, month = {apr}, keywords = {2008, Multiple Fellows}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v100/i15/e150401}, author = {Lundblad, N. and Patricia J Lee and Ian B Spielman and Benjamin L Brown and William D Phillips and J V Porto} } @article {Spielman2008, title = {Condensate Fraction in a 2D Bose Gas Measured across the Mott-Insulator Transition}, journal = {Phys. Rev. Lett.}, volume = {100}, number = {12}, year = {2008}, month = {mar}, keywords = {2008, Multiple Fellows}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v100/i12/e120402}, author = {Ian B Spielman and William D Phillips and J V Porto} } @article {Lang2008, title = {Cruising through molecular bound-state manifolds with radiofrequency}, journal = {Nat. Phys.}, volume = {4}, number = {3}, year = {2008}, month = {jan}, pages = {223{\textendash}226}, publisher = {Nature Publishing Group}, abstract = {The production of ultracold molecules with their rich internal structure is currently attracting considerable interest1, 2, 3, 4. For future experiments, it will be important to efficiently transfer these molecules from their initial internal quantum state at production to other quantum states of interest. Transfer tools such as optical Raman schemes5, 6, radiofrequency transitions (see, for example, ref.~7) or magnetic field ramping8, 9 exist, but are either technically involved or limited in their applicability. Here, we demonstrate a simple, highly efficient hybrid transfer method that overcomes a number of the previous limitations. The scheme is based on magnetically tuned mixing of two neighbouring molecular levels, which enables otherwise forbidden radiofrequency transitions between them. By repeating this process at various magnetic fields, molecules can be successively transported through a large manifold of quantum states. Applying nine transfers, we convert very weakly bound Feshbach molecules to a much more deeply bound level with a binding energy corresponding to 3.6~GHz. As an important spin-off of our experiments, we demonstrate a high-precision spectroscopy method for investigating level crossings.}, keywords = {2008, Single Fellow}, issn = {1745-2473}, url = {http://dx.doi.org/10.1038/nphys838}, author = {Lang, F. and Straten, P. v. d. and Brandst{\"a}tter, B. and Thalhammer, G. and Winkler, K. and Paul S Julienne and Rudolf Grimm and J Hecker Denschlag} } @article { ISI:000258538600045, title = {Effective masses in a strongly anisotropic Fermi liquid}, journal = {PHYSICAL REVIEW LETTERS}, volume = {101}, number = {6}, year = {2008}, month = {AUG 8}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.101.066405}, author = {Stanescu, Tudor D. and Victor M Galitski and Drew, H. D.} } @article {2472, title = {Emission Spectrum of a Dressed Exciton-Biexciton Complex in a Semiconductor Quantum Dot}, journal = {Phys. Rev. Lett.}, volume = {101}, year = {2008}, month = {7/2008}, pages = {027401}, doi = {10.1103/PhysRevLett.101.027401}, author = {Andreas Muller and Wei Fang and John R Lawall and Glenn S Solomon} } @article {Scarola2008, title = {Emulating non-Abelian topological matter in cold-atom optical lattices}, journal = {Phys. Rev. A}, volume = {77}, number = {2}, year = {2008}, month = {feb}, abstract = {Certain proposed extended Bose-Hubbard models may exhibit topologically ordered ground states with excitations obeying non-Abelian braid statistics. A sufficient tuning of Hubbard parameters could yield excitation braiding rules allowing implementation of a universal set of topologically protected quantum gates. We discuss potential difficulties in realizing a model with a proposed non-Abelian topologically ordered ground state using optical lattices containing bosonic dipoles. Our direct implementation scheme does not realize the necessary anisotropic hopping, anisotropic interactions, and low temperatures.}, keywords = {2008, Single Fellow}, issn = {1050-2947}, url = {http://arxiv.org/abs/0707.4435}, author = {V W Scarola and S. Das Sarma} } @article {DeMille2008, title = {Enhanced Sensitivity to Variation of me/mp in Molecular Spectra}, journal = {Phys. Rev. Lett.}, volume = {100}, number = {4}, year = {2008}, month = {jan}, keywords = {2008, Single Fellow}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v100/i4/e043202}, author = {DeMille, D and Sainis, S and Sage, J and Bergeman, T and Svetlana Kotochigova and Eite Tiesinga} } @article {Brida2008, title = {Experimental test of nonclassicality for a single particle}, journal = {Optics Express}, volume = {16}, number = {16}, year = {2008}, month = {jul}, pages = {11750}, abstract = {In a recent paper [R. Alicki and N. Van Ryn, J. Phys. A: Math. Theor., 41, 062001 (2008)] a test of nonclassicality for a single qubit was proposed. Here, we discuss the class of local realistic theories to which this test applies and present an experimental realization.}, keywords = {2008, Single Fellow}, issn = {1094-4087}, url = {http://arxiv.org/abs/0804.1646}, author = {Giorgio Brida and Ivo P Degiovanni and Marco Genovese and Valentina Schettini and Sergey V Polyakov and Alan L Migdall} } @article {Wille2008, title = {Exploring an Ultracold Fermi-Fermi Mixture: Interspecies Feshbach Resonances and Scattering Properties of Li6 and K40}, journal = {Phys. Rev. Lett.}, volume = {100}, number = {5}, year = {2008}, month = {feb}, keywords = {2008, Multiple Fellows}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v100/i5/e053201}, author = {Wille, E. and Spiegelhalder, F. and Kerner, G. and Naik, D and Trenkwalder, A and Hendl, G and Schreck, F and Rudolf Grimm and Tiecke, T. and Walraven, J. and Kokkelmans, S. and Eite Tiesinga and Paul S Julienne} } @article {2471, title = {Generating entanglement between quantum dots with different resonant frequencies based on dipole-induced transparency}, journal = {Phys Rev. A}, volume = {78}, year = {2008}, month = {11/2008}, pages = {052321}, doi = {10.1103/PhysRevA.78.052321}, author = {Deepak Sridharan and Edo Waks} } @article { ISI:000259377500042, title = {Incommensurate superfluidity of bosons in a double-well optical lattice}, journal = {PHYSICAL REVIEW LETTERS}, volume = {101}, number = {12}, year = {2008}, month = {SEP 19}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.101.125301}, author = {Stojanovic, Vladimir M. and Wu, Congjun and Liu, W. Vincent and S. Das Sarma} } @article {Shaw2008, title = {Kinetics of nonequilibrium quasiparticle tunneling in superconducting charge qubits}, journal = {Phys. Rev. B}, volume = {78}, number = {2}, year = {2008}, month = {jul}, keywords = {2008, No Fellows}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v78/i2/e024503}, author = {M D Shaw and Roman M Lutchyn and Delsing, P. and P M Echternach} } @conference {Polyakov2008, title = {Multiplexed photon-counting detectors}, booktitle = {Proceedings of the SPIE}, volume = {6900}, year = {2008}, month = {jan}, pages = {690019{\textendash}690019{\textendash}8}, publisher = {SPIE}, organization = {SPIE}, keywords = {2008, Single Fellow}, issn = {0277786X}, url = {http://adsabs.harvard.edu/abs/2008SPIE.6900E..26P}, author = {Sergey V Polyakov and Valentina Schettini and Ivo P Degiovanni and Giorgio Brida and Alan L Migdall} } @article {Civelli2008, title = {Nodal-Antinodal Dichotomy and the Two Gaps of a Superconducting Doped Mott Insulator}, journal = {Phys. Rev. Lett.}, volume = {100}, number = {4}, year = {2008}, month = {jan}, pages = {5}, abstract = {We study the superconducting state of the hole-doped two-dimensional Hubbard model using Cellular Dynamical Mean Field Theory, with the Lanczos method as impurity solver. In the under-doped regime, we find a natural decomposition of the one-particle (photoemission) energy-gap into two components. The gap in the nodal regions, stemming from the anomalous self-energy, decreases with decreasing doping. The antinodal gap has an additional contribution from the normal component of the self-energy, inherited from the normal-state pseudogap, and it increases as the Mott insulating phase is approached.}, keywords = {2008, No Fellows}, issn = {0031-9007}, url = {http://arxiv.org/abs/0704.1486}, author = {Civelli, M. and Capone, M. and Georges, A. and Haule, K. and Parcollet, O. and Tudor D Stanescu and Kotliar, G.} } @article { ISI:000259377800008, title = {Non-Abelian anyons and topological quantum computation}, journal = {REVIEWS OF MODERN PHYSICS}, volume = {80}, number = {3}, year = {2008}, month = {JUL-SEP}, pages = {1083-1159}, issn = {0034-6861}, doi = {10.1103/RevModPhys.80.1083}, author = {Nayak, Chetan and Simon, Steven H. and Stern, Ady and Freedman, Michael and S. Das Sarma} } @article {Gomez2008, title = {Nuclear Magnetic Moment of Fr210: A Combined Theoretical and Experimental Approach}, journal = {Phys. Rev. Lett.}, volume = {100}, number = {17}, year = {2008}, month = {may}, keywords = {2008, Single Fellow}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v100/i17/e172502}, author = {Gomez, E. and Aubin, S. and Luis A Orozco and G Sprouse and Iskrenova-Tchoukova, E. and Marianna S Safronova} } @article { ISI:000261141500052, title = {Pairing Symmetry and Josephson Current in Doped 2-Leg t-J Ladders}, journal = {PHYSICAL REVIEW LETTERS}, volume = {101}, number = {21}, year = {2008}, month = {NOV 21}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.101.217001}, author = {Feiguin, A. E. and White, S. R. and Scalapino, D. J. and Affleck, I.} } @article {Satija2008, title = {Physics of a two-dimensional electron gas with cold atoms in non-Abelian gauge potentials}, journal = {Phys. Rev. A}, volume = {77}, number = {4}, year = {2008}, month = {apr}, abstract = {Motivated by the possibility of creating non-Abelian fields using cold atoms in optical lattices, we explore the richness and complexity of non-interacting two-dimensional electron gases (2DEGs) in a lattice, subjected to such fields. In the continuum limit, a non-Abelian system characterized by a two-component "magnetic flux" describes a harmonic oscillator existing in two different charge states (mimicking a particle-hole pair) where the coupling between the states is determined by the non-Abelian parameter, namely the difference between the two components of the "magnetic flux." A key feature of the non-Abelian system is a splitting of the Landau energy levels, which broaden into bands, as the spectrum depends explicitly on the transverse momentum. These Landau bands result in a coarse-grained "moth," a continuum version of the generalized Hofstadter butterfly. Furthermore, the bands overlap, leading to effective relativistic effects. Importantly, similar features also characterize the corresponding two-dimensional lattice problem when at least one of the components of the magnetic flux is an irrational number. The lattice system with two competing "magnetic fluxes" penetrating the unit cell provides a rich environment in which to study localization phenomena. Some unique aspects of the transport properties of the non-Abelian system are the possibility of inducing localization by varying the quasimomentum, and the absence of localization of certain zero-energy states exhibiting a linear energy-momentum relation. Furthermore, non-Abelian systems provide an interesting localization scenario where the localization transition is accompanied by a transition from relativistic to non-relativistic theory.}, keywords = {2008, Single Fellow}, issn = {1050-2947}, url = {http://arxiv.org/abs/0711.2433}, author = {Indubala Satija and Dakin, Daniel and J Vaishnav and Charles W Clark} } @article {Mitra2008, title = {Quantum behavior of a dc SQUID phase qubit}, journal = {Phys. Rev. B}, volume = {77}, number = {21}, year = {2008}, month = {jun}, keywords = {2008, CMAMO, Multiple Fellows}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v77/i21/e214512}, author = {Kaushik Mitra and Frederick W Strauch and Christopher J Lobb and Jeffrey R Anderson and F C Wellstood and Eite Tiesinga} } @article {Danshita2008, title = {Reentrant quantum phase transition in double-well optical lattices}, journal = {Phys. Rev. A}, volume = {77}, number = {6}, year = {2008}, month = {jun}, keywords = {2008, Single Fellow}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v77/i6/e063609}, author = {Ippei Danshita and C A R S{\'a} de Melo and Charles W Clark} } @article {Sengupta2008, title = {Spontaneous Spin Accumulation in Singlet-Triplet Josephson Junctions}, journal = {Phys. Rev. Lett.}, volume = {101}, number = {18}, year = {2008}, month = {oct}, keywords = {2008, Single Fellow}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v101/i18/e187003}, author = {K Sengupta and Victor M Yakovenko} } @article {Strauch2008a, title = {Theoretical analysis of perfect quantum state transfer with superconducting qubits}, journal = {Phys. Rev. B}, volume = {78}, number = {9}, year = {2008}, month = {sep}, keywords = {2008, Single Fellow}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v78/i9/e094516}, author = {Frederick W Strauch and Carl J Williams} } @article {Strauch2008, title = {Tunneling phase gate for neutral atoms in a double-well lattice}, journal = {Phys. Rev. A}, volume = {77}, number = {5}, year = {2008}, month = {may}, keywords = {2008, Multiple Fellows}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v77/i5/e050304}, author = {Frederick W Strauch and Edwards, Mark and Eite Tiesinga and Carl J Williams and Charles W Clark} } @article {Galvan2008, title = {Two-color modulation transfer spectroscopy}, year = {2008}, month = {dec}, pages = {14}, abstract = {We present two-color modulation transfer spectroscopy as a tool for precision studies of atomic properties of excited states. The bi-colored technique addresses a narrow set of velocity groups of a thermal atomic vapour using a two-step transition to "burn a hole" in the velocity distribution. The resulting spectrum presents sub-Doppler linewidths, good signal to noise ratio and the trademark sidebands that work as an in situ ruler for the energy spacing between atomic resonances. The spectra obtained can be used for different applications such as measurements of energy splittings or stabilization of laser frequencies to excited atomic transitions.}, keywords = {2008}, url = {http://arxiv.org/abs/0812.1386}, author = {Galvan, A. Perez and Dong Sheng and Luis A Orozco and Zhao, Y} } @conference {HillIII2007, title = {All-optical manipulation of neutral atomic ensembles}, booktitle = {Proceedings of the SPIE}, volume = {6644}, number = {1}, year = {2007}, month = {sep}, pages = {664411{\textendash}664411{\textendash}10}, publisher = {SPIE}, organization = {SPIE}, keywords = {2007, Single Fellow}, issn = {0277786X}, url = {http://link.aip.org/link/?PSISDG/6644/664411/1}, author = {Wendell T Hill III and Narupon Chattrapiban and Arakelyan, I. V. and Mitra, S. and Song, Y.} } @article {Zhang2007a, title = {Anyonic braiding in optical lattices}, journal = {PNAS}, volume = {104}, number = {47}, year = {2007}, month = {nov}, pages = {18415{\textendash}20}, abstract = {Topological quantum states of matter, both Abelian and non-Abelian, are characterized by excitations whose wavefunctions undergo nontrivial statistical transformations as one excitation is moved (braided) around another. Topological quantum computation proposes to use the topological protection and the braiding statistics of a non-Abelian topological state to perform quantum computation. The enormous technological prospect of topological quantum computation provides new motivation for experimentally observing a topological state. Here, we explicitly work out a realistic experimental scheme to create and braid the Abelian topological excitations in the Kitaev model built on a tunable robust system, a cold atom optical lattice. We also demonstrate how to detect the key feature of these excitations: their braiding statistics. Observation of this statistics would directly establish the existence of anyons, quantum particles that are neither fermions nor bosons. In addition to establishing topological matter, the experimental scheme we develop here can also be adapted to a non-Abelian topological state, supported by the same Kitaev model but in a different parameter regime, to eventually build topologically protected quantum gates.}, keywords = {2007, Single Fellow}, issn = {1091-6490}, url = {http://www.pnas.org/cgi/content/abstract/104/47/18415}, author = {Zhang, Chuanwei and V W Scarola and Tewari, Sumanta and S. Das Sarma} } @article {Arora2007, title = {Blackbody-radiation shift in a \^\43\Ca\^\+\ ion optical frequency standard}, journal = {Phys. Rev. A}, volume = {76}, number = {6}, year = {2007}, month = {dec}, keywords = {2007, Single Fellow}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v76/i6/e064501}, author = {Arora, Bindiya and Marianna S Safronova and Charles W Clark} } @conference {KrzysztofSzymaniec2007, title = {Cancellation of the Collisional Frequency Shift in Caesium Fountain Clocks - OSA Technical Digest (CD)}, booktitle = {Conference on Coherence and Quantum Optics}, year = {2007}, month = {jun}, pages = {CSuA13}, publisher = {Optical Society of America}, organization = {Optical Society of America}, abstract = {We have observed the cancellation of the collisional frequency shift in primary caesium fountain clocks. We present systematic experimental study of the effect and a theoretical model explaining our observations.}, keywords = {2007, and metrology, Atomic and molecular physics, Effects of collisions, Instrumentation, measurement, Metrology, Multiple Fellows}, url = {http://www.opticsinfobase.org/abstract.cfm?URI=CQO-2007-CSuA13}, author = {Krzysztof Szymaniec and Witold Chalupczak and Eite Tiesinga and Carl J Williams and Stefan Weyers and Robert Wynands} } @article {PEREZGALVAN2007, title = {Comparison of hyperfine anomalies in the 5S1/25S1/2 and 6S1/26S1/2 levels of 85Rb and 87Rb}, journal = {Phys. Lett. B}, volume = {655}, number = {3-4}, year = {2007}, month = {nov}, pages = {114{\textendash}118}, abstract = {We observe a hyperfine anomaly in the measurement of the hyperfine splitting of the 6S1/2 excited level in rubidium. We perform two step spectroscopy using the 5S1/2{\textrightarrow}5P1/2{\textrightarrow}6S1/2 excitation sequence. We measure the splitting of the 6S1/2 level and obtain for the magnetic dipole constants of 85Rb and 87Rb and , respectively. The hyperfine anomaly difference of comes from the Bohr Weisskopf effect: a correction to the point interaction between the finite nuclear magnetization and the electrons, and agrees with that obtained in the 5S1/2 ground state.}, keywords = {2007, 21.60.-n, 32.10.fn, 32.30.-r, Single Fellow}, issn = {03702693}, url = {http://dx.doi.org/10.1016/j.physletb.2007.09.042}, author = {A P{\'e}rez Galv{\'a}n and Zhao, Y and Luis A Orozco and Gomez, E. and A Lange and F Baumer and G Sprouse} } @article {Fang2007, title = {Control of lasing in fully chaotic open microcavities by tailoring the shape factor}, journal = {Appl. Phys. Lett.}, volume = {90}, number = {8}, year = {2007}, month = {feb}, pages = {081108}, keywords = {2007, gallium arsenide, III-V semiconductors, laser frequency stability, laser modes, microcavity lasers, optical chaos, optical pumping, Q-factor, semiconductor lasers, Single Fellow}, issn = {00036951}, url = {http://link.aip.org/link/?APPLAB/90/081108/1}, author = {Wei Fang and Hui Cao and Glenn S Solomon} } @article {Anderlini2007, title = {Controlled exchange interaction between pairs of neutral atoms in an optical lattice}, journal = {Nature}, volume = {448}, number = {7152}, year = {2007}, month = {jul}, pages = {452{\textendash}6}, abstract = {Ultracold atoms trapped by light offer robust quantum coherence and controllability, providing an attractive system for quantum information processing and for the simulation of complex problems in condensed matter physics. Many quantum information processing schemes require the manipulation and deterministic entanglement of individual qubits; this would typically be accomplished using controlled, state-dependent, coherent interactions among qubits. Recent experiments have made progress towards this goal by demonstrating entanglement among an ensemble of atoms confined in an optical lattice. Until now, however, there has been no demonstration of a key operation: controlled entanglement between atoms in isolated pairs. Here we use an optical lattice of double-well potentials to isolate and manipulate arrays of paired (87)Rb atoms, inducing controlled entangling interactions within each pair. Our experiment realizes proposals to use controlled exchange coupling in a system of neutral atoms. Although 87Rb atoms have nearly state-independent interactions, when we force two atoms into the same physical location, the wavefunction exchange symmetry of these identical bosons leads to state-dependent dynamics. We observe repeated interchange of spin between atoms occupying different vibrational levels, with a coherence time of more than ten milliseconds. This observation demonstrates the essential component of a neutral atom quantum SWAP gate (which interchanges the state of two qubits). Its {\textquoteright}half-implementation{\textquoteright}, the root SWAP gate, is entangling, and together with single-qubit rotations it forms a set of universal gates for quantum computation.}, keywords = {2007, Multiple Fellows}, issn = {1476-4687}, url = {http://dx.doi.org/10.1038/nature06011}, author = {Anderlini, M. and Patricia J Lee and Benjamin L Brown and Jennifer Sebby-Strabley and William D Phillips and J V Porto} } @article {Arora2007b, title = {Determination of electric-dipole matrix elements in K and Rb from Stark shift measurements}, journal = {Phys. Rev. A}, volume = {76}, number = {5}, year = {2007}, month = {nov}, keywords = {2007, Single Fellow}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v76/i5/e052516}, author = {Arora, Bindiya and Marianna S Safronova and Charles W Clark} } @article {Scarola2007, title = {Edge Transport in 2D Cold Atom Optical Lattices}, journal = {Phys. Rev. Lett.}, volume = {98}, number = {21}, year = {2007}, month = {may}, abstract = {We theoretically study the observable response of edge currents in two dimensional cold atom optical lattices. As an example we use Gutzwiller mean-field theory to relate persistent edge currents surrounding a Mott insulator in a slowly rotating trapped Bose-Hubbard system to time of flight measurements. We briefly discuss an application, the detection of Chern number using edge currents of a topologically ordered optical lattice insulator.}, keywords = {2007, Single Fellow}, issn = {0031-9007}, url = {http://arxiv.org/abs/cond-mat/0612302}, author = {V W Scarola and S. Das Sarma} } @article {Rey2007, title = {Entanglement and the Mott transition in a rotating bosonic ring lattice}, journal = {Phys. Rev. A}, volume = {75}, number = {6}, year = {2007}, month = {jun}, keywords = {2007, Single Fellow}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v75/i6/e063616}, author = {A M Rey and Burnett, Keith and Indubala Satija and Charles W Clark} } @article {Xie2007, title = {Influence of a single quantum dot state on the characteristics of a microdisk laser}, journal = {Phys. Rev. Lett.}, volume = {98}, number = {11}, year = {2007}, month = {mar}, pages = {117401}, abstract = {We report a quantum dot microcavity laser with a cw sub-microW lasing threshold, where a significant reduction of the lasing threshold is observed when a single quantum dot (QD) state is aligned with a cavity mode. The quality factor exceeds 15,000 before the system lases. When no QD states are resonant, below threshold the cavity mode initially degrades with increasing pump power, after which saturation occurs and then the cavity mode recovers. We associate the initial cavity mode spoiling with QD state broadening that occurs with increasing pump power.}, keywords = {2007, Single Fellow}, issn = {0031-9007}, url = {http://www.ncbi.nlm.nih.gov/pubmed/17501091}, author = {Xie, Z G and Stephan G{\"o}tzinger and Wei Fang and Hui Cao and Glenn S Solomon} } @article {Zhang2007, title = {Initializing a quantum register from Mott-insulator states in optical lattices}, journal = {Phys. Rev. A}, volume = {75}, number = {6}, year = {2007}, pages = {7}, abstract = {We propose a technique to measure multi-spin correlation functions of arbitrary range as determined by the ground states of spinful cold atoms in optical lattices. We show that an observation of the atomic version of the Stokes parameters, using focused lasers and microwave pulsing, can be related to \$n\$-spin correlators. We discuss the possibility of detecting not only ground state static spin correlations, but also time-dependent spin wave dynamics as a demonstrative example using our proposed technique.}, keywords = {2007, Single Fellow}, issn = {1050-2947}, url = {http://arxiv.org/abs/cond-mat/0611689 http://pra.aps.org/abstract/PRA/v75/i6/e060301}, author = {Zhang, Chuanwei and V W Scarola and S. Das Sarma} } @book {Schmidt2007, title = {Lateral Aligment of Epitaxial Quantum Dots}, series = {Nano Science and Technology}, year = {2007}, pages = {691{\textendash}707}, publisher = {Springer Berlin Heidelberg}, organization = {Springer Berlin Heidelberg}, address = {Berlin, Heidelberg}, abstract = {It is naturally of interest to extend the successful integration of quantum wells (QWs) in epitaxial semiconductor structures to more highly confined systems, such as quantum wires (QWRs) and quantum dots (QDs). However, the precision in the epitaxial crystal growth used to fabricate QWs is on the order of the crystal monolayer (ML), higher than the current lithography techniques that are required to form QWRs and QDs. In addition, in these more dimensionally reduced systems the surface area to volume ratio is increased, and poorly terminated surfaces, due to either exposed free surface or process-related damage, diminish the quality. Coupling these problems with the fact that typically only a few QWs are used together, while typically much more QDs will be required to achieve equivalent output power, it becomes clear why progress in this area has been slow. Crystal growth techniques have been used with varying success over the last decade to produce one- and zero-dimensional structures. Colloidal systems have produced QD ensembles [1] with inhomogeneous broadening and are difficult to integrate into epitaxial systems common to solid state devices. Regrowth on patterned substrates has been used to produce QWRs [2] and the patterned regions above QWs have been used as stressors to form QDs from the QW [3]. Finally, ensembles of QDs have been formed by strainenhanced surface diffusion [4], and ordering has been observed using the (311) surface [5].

}, keywords = {2007, Chemistry and Materials Science, Single Fellow}, url = {http://www.springerlink.com/content/g0tu5hj514427q81/}, author = {Schmidt, Oliver} } @article {Arora2007a, title = {Magic wavelengths for the np-ns transitions in alkali-metal atoms}, journal = {Phys. Rev. A}, volume = {76}, number = {5}, year = {2007}, month = {nov}, keywords = {2007, Single Fellow}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v76/i5/e052509}, author = {Arora, Bindiya and Marianna S Safronova and Charles W Clark} } @article {Zhang2007c, title = {Magnetism and anomalous Hall effect in Co-(La,Sr)TiO3}, journal = {Phys. Rev. B}, volume = {76}, number = {8}, year = {2007}, month = {aug}, pages = {85323}, keywords = {2007, and superparamagnetism, Diamagnetism, Galvanomagnetic and other magnetotransport effects, Magnetic semiconductors, No Fellows, paramagnetism}, issn = {1098-0121}, url = {http://adsabs.harvard.edu/abs/2007PhRvB..76h5323Z}, author = {Zhang, S. and Yu, W. and Ogale, S. and Shinde, S. and Kundaliya, D. and Tse, Wang-Kong and Young, S. and Higgins, J. and Salamanca-Riba, L. and Herrera, M. and Fu, L. and Browning, N. and Greene, R. and Venkatesan, T.} } @article {Tan2007, title = {Measurement of Scattering Rate and Minimum Conductivity in Graphene}, journal = {Phys. Rev. Lett.}, volume = {99}, number = {24}, year = {2007}, month = {dec}, keywords = {2007, Single Fellow}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v99/i24/e246803}, author = {Tan, Y.-W. and Zhang, Y. and Bolotin, K. and Zhao, Y and Shaffique Adam and E H Hwang and S. Das Sarma and Stormer, H. L. and Kim, P.} } @article {Solomon2007, title = {Microcavity modified spontaneous emission of single quantum dots}, journal = {Phys. Status Solidi B}, volume = {244}, number = {8}, year = {2007}, month = {aug}, pages = {2792{\textendash}2802}, keywords = {2007, Single Fellow}, issn = {03701972}, url = {http://doi.wiley.com/10.1002/pssb.200675619}, author = {Glenn S Solomon and Matthew Pelton and Yoshihisa Yamamoto} } @article {Spielman2007, title = {Mott-Insulator Transition in a Two-Dimensional Atomic Bose Gas}, journal = {Phys. Rev. Lett.}, volume = {98}, number = {8}, year = {2007}, month = {feb}, keywords = {2007, Multiple Fellows}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v98/i8/e080404}, author = {Ian B Spielman and William D Phillips and J V Porto} } @article {Rey2007a, title = {Noise correlations of fermions and hard core bosons in a quasi-periodic potential}, journal = {Laser Physics}, volume = {17}, number = {2}, year = {2007}, month = {feb}, pages = {205{\textendash}210}, keywords = {2007, Single Fellow}, issn = {1054-660X}, url = {http://adsabs.harvard.edu/abs/2007LaPhy..17..205R}, author = {A M Rey and Indubala Satija and Charles W Clark} } @article {Stanescu2007a, title = {Nonequilibrium Spin Dynamics in a Trapped Fermi Gas with Effective Spin-Orbit Interactions}, journal = {Phys. Rev. Lett.}, volume = {99}, number = {11}, year = {2007}, month = {sep}, keywords = {2007, Single Fellow}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v99/i11/e110403}, author = {Tudor D Stanescu and Zhang, Chuanwei and Victor M Galitski} } @article {Sebby-Strabley2007, title = {Preparing and Probing Atomic Number States with an Atom Interferometer}, journal = {Phys. Rev. Lett.}, volume = {98}, number = {20}, year = {2007}, month = {may}, keywords = {2007, Multiple Fellows}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v98/i20/e200405}, author = {Jennifer Sebby-Strabley and Benjamin L Brown and Anderlini, M. and Patricia J Lee and William D Phillips and J V Porto and Philip R Johnson} } @article { ISI:000249154900116, title = {Probing n-spin correlations in optical lattices}, journal = {PHYSICAL REVIEW A}, volume = {76}, number = {2}, year = {2007}, month = {AUG}, issn = {1050-2947}, doi = {10.1103/PhysRevA.76.023605}, author = {Zhang, Chuanwei and Scarola, V. W. and S. Das Sarma} } @conference { ISI:000246281800538, title = {Quantum control of donor-bound electrons at the Si-SiO2 interface}, booktitle = {Physics of Semiconductors, Pts A and B}, series = {AIP CONFERENCE PROCEEDINGS}, volume = {893}, year = {2007}, note = {28th International Conference on the Physics of Semiconductors (ICPS-28), Vienna, AUSTRIA, JUL 24-28, 2006}, pages = {1095-1096}, isbn = {978-0-7354-0397-0}, issn = {0094-243X}, author = {Koiller, Belita and Calderon, M. J. and Hu, Xuedong and S. Das Sarma}, editor = {Jantsch, W and Schaffler, F} } @article {Danshita2007, title = {Quantum phases of bosons in double-well optical lattices}, journal = {Phys. Rev. A}, volume = {76}, number = {4}, year = {2007}, month = {oct}, keywords = {2007, Single Fellow}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v76/i4/e043606}, author = {Ippei Danshita and James E Williams and C A R S{\'a} de Melo and Charles W Clark} } @article {Castelletto2007, title = {Reduced deadtime and higher rate photon-counting detection using a multiplexed detector array}, journal = {Journal of Modern Optics}, volume = {54}, number = {2-3}, year = {2007}, month = {jan}, pages = {337{\textendash}352}, abstract = {We present a scheme for a photon-counting detection system that can be operated at incident photon rates higher than otherwise possible by suppressing the effects of detector deadtime. The method uses an array of N detectors and a 1-by-N optical switch with a control circuit to direct input light to live detectors. Our calculations and models highlight the advantages of the technique. In particular, using this scheme, a group of N detectors provides an improvement in operation rate that can exceed the improvement that would be obtained by a single detector with deadtime reduced by 1/N, even if it were feasible to produce a single detector with such a large improvement in deadtime. We model the system for continuous and pulsed light sources, both of which are important for quantum metrology and quantum key distribution applications.}, keywords = {2007, Single Fellow}, issn = {0950-0340}, url = {http://arxiv.org/abs/quant-ph/0601102}, author = {Stefania A Castelletto and Ivo P Degiovanni and Valentina Schettini and Alan L Migdall} } @article {Deng2007, title = {Spatial Coherence of a Polariton Condensate}, journal = {Phys. Rev. Lett.}, volume = {99}, number = {12}, year = {2007}, month = {sep}, abstract = {We perform Young{\textquoteright}s double-slit experiment to study the spatial coherence properties of a two-dimensional dynamic condensate of semiconductor microcavity polaritons. The coherence length of the system is measured as a function of the pump rate, which confirms a spontaneous buildup of macroscopic coherence in the condensed phase. An independent measurement reveals that the position and momentum uncertainty product of the condensate is close to the Heisenberg limit. An experimental realization of such a minimum uncertainty wave packet of the polariton condensate opens a door to coherent matter-wave phenomena such as Josephson oscillation, superfluidity, and solitons in solid state condensate systems.}, keywords = {2007, Single Fellow}, issn = {0031-9007}, url = {http://arxiv.org/abs/cond-mat/0703508}, author = {Deng, Hui and Glenn S Solomon and Hey, Rudolf and Ploog, Klaus and Yoshihisa Yamamoto} } @inbook {springerlink:10.1007/978-3-540-46936-0_26, title = {Spatial InAs Quantum Dot Positioning in GaAs Microdisk and Posts}, booktitle = {Lateral Alignment of Epitaxial Quantum Dots}, series = {NanoScience and Technology}, year = {2007}, pages = {691{\textendash}707}, publisher = {Springer Berlin Heidelberg}, organization = {Springer Berlin Heidelberg}, keywords = {2007, Single Fellow}, doi = {10.1007/978-3-540-46936-0_26}, author = {Schmidt, Oliver} } @article {Stanescu2007, title = {Spin relaxation in a generic two-dimensional spin-orbit coupled system}, journal = {Phys. Rev. B}, volume = {75}, number = {12}, year = {2007}, month = {mar}, keywords = {2007, Single Fellow}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v75/i12/e125307}, author = {Tudor D Stanescu and Victor M Galitski} } @article {Palmer2007, title = {Steady-state thermodynamics of nonequilibrium quasiparticles in a Cooper-pair box}, journal = {Phys. Rev. B}, volume = {76}, number = {5}, year = {2007}, month = {aug}, keywords = {2007, Single Fellow}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v76/i5/e054501}, author = {B S Palmer and Sanchez, C. and Naik, A. and Manheimer, M. and J F Schneiderman and P M Echternach and F C Wellstood} } @article {Silva2007, title = {Stochastic volatility of financial markets as the fluctuating rate of trading: An empirical study}, journal = {Physica A: Statistical Mechanics and its Applications}, volume = {382}, number = {1}, year = {2007}, month = {aug}, pages = {278{\textendash}285}, abstract = {We present an empirical study of the subordination hypothesis for a stochastic time series of a stock price. The fluctuating rate of trading is identified with the stochastic variance of the stock price, as in the continuous-time random walk (CTRW) framework. The probability distribution of the stock price changes (log-returns) for a given number of trades N is found to be approximately Gaussian. The probability distribution of N for a given time interval Dt is non-Poissonian and has an exponential tail for large N and a sharp cutoff for small N. Combining these two distributions produces a nontrivial distribution of log-returns for a given time interval Dt, which has exponential tails and a Gaussian central part, in agreement with empirical observations.}, keywords = {2007, Single Fellow}, issn = {03784371}, url = {http://arxiv.org/abs/physics/0608299}, author = {Silva, A. Christian and Victor M Yakovenko} } @article {Palomaki2007, title = {Strong-Field Effects in the Rabi Oscillations of the Superconducting Phase Qubit}, journal = {IEEE Transactions on Applied Superconductivity}, volume = {17}, number = {2}, year = {2007}, month = {jun}, pages = {162{\textendash}165}, abstract = {We have used 2 ns pulses of current to read out the states of a Nb/AlOx/Nb dc SQUID phase qubit at 25 mK. Plotting the number of escape events that occur versus the size of the current pulse reveals a series of steps corresponding to the occupancy of different energy levels. After calibrating the measurement pulses, we fit these steps to determine the population in each level. Rabi oscillations were viewed using this technique. The single-shot measurement fidelity was theoretically analysed and the optimal single pulse in our device was determined.}, keywords = {2007, Multiple Fellows}, issn = {1051-8223}, url = {http://adsabs.harvard.edu/abs/2007ITAS...17..105S http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=4277655}, author = {T A Palomaki and S K Dutta and R M Lewis and Hanhee Paik and Kaushik Mitra and Benjamin K Cooper and Przybysz, A.J. and Dragt, A. J. and Jeffrey R Anderson and Christopher J Lobb and F C Wellstood and Frederick W Strauch} } @article {Lee2007a, title = {Sublattice Addressing and Spin-Dependent Motion of Atoms in a Double-Well Lattice}, journal = {Phys. Rev. Lett.}, volume = {99}, number = {2}, year = {2007}, month = {jul}, keywords = {2007, Multiple Fellows}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v99/i2/e020402}, author = {Patricia J Lee and Anderlini, M. and Benjamin L Brown and Jennifer Sebby-Strabley and William D Phillips and J V Porto} } @article {Stanescu2007b, title = {Theory of the Luttinger surface in doped Mott insulators}, journal = {Phys. Rev. B}, volume = {75}, number = {10}, year = {2007}, month = {mar}, keywords = {2007, No Fellows}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v75/i10/e104503}, author = {Tudor D Stanescu} } @article {Manfra2007, title = {Transport and Percolation in a Low-Density High-Mobility Two-Dimensional Hole System}, journal = {Phys. Rev. Lett.}, volume = {99}, number = {23}, year = {2007}, month = {dec}, keywords = {2007, Single Fellow}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v99/i23/e236402}, author = {Manfra, M. and E H Hwang and S. Das Sarma and Pfeiffer, L. and West, K. and Sergent, A.} } @conference {Castelletto2006a, title = {Achieving higher photon counting rates using multiplexed detectors}, booktitle = {Proceedings of the SPIE}, volume = {6305}, year = {2006}, month = {aug}, pages = {63050R{\textendash}63050R{\textendash}7}, publisher = {SPIE}, organization = {SPIE}, keywords = {2006, Single Fellow}, issn = {0277786X}, url = {http://adsabs.harvard.edu/abs/2006SPIE.6305E..20C}, author = {Stefania A Castelletto and Ivo P Degiovanni and Alan L Migdall and Sergey V Polyakov and Valentina Schettini} } @conference {Cao2006, title = {Chaotic Microcavity Lasers}, booktitle = {2006 IEEE LEOS Annual Meeting Conference Proceedings}, year = {2006}, month = {oct}, pages = {727{\textendash}728}, publisher = {IEEE}, organization = {IEEE}, abstract = {In this talk, we demonstrate that the lasing threshold in a semiconductor microstadium can be minimized by tuning its shape. Contrary to common expectation, modes of such a completely open fully chaotic microcavity may have long lifetime. As the dielectric microstadium represents a completely open fully chaotic cavity, this work opens the door to control chaotic microcavity lasers by tailoring its shape}, keywords = {2006, Single Fellow}, url = {http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=4054390}, author = {Hui Cao and Wei Fang and Glenn S Solomon} } @article { ISI:000237147700026, title = {Cold-atom optical lattices as quantum analog simulators for aperiodic one-dimensional localization without disorder}, journal = {PHYSICAL REVIEW A}, volume = {73}, number = {4}, year = {2006}, month = {APR}, issn = {1050-2947}, doi = {10.1103/PhysRevA.73.041609}, author = {Scarola, VW and S. Das Sarma} } @article {Spielman2006, title = {Collisional deexcitation in a quasi-two-dimensional degenerate bosonic gas}, journal = {Phys. Rev. A}, volume = {73}, number = {2}, year = {2006}, pages = {2{\textendash}5}, publisher = {APS}, keywords = {2006, Multiple Fellows}, issn = {1050-2947}, url = {http://www.mendeley.com/research/collisional-deexcitation-in-a-quasitwodimensional-degenerate-bosonic-gas/}, author = {Ian B Spielman and Philip R Johnson and J H Huckans and Fertig, C. and Steven L Rolston and William D Phillips and J V Porto} } @article {Anderlini2006, title = {Controlled atom dynamics in a double-well optical lattice}, journal = {J. Phys. B: At. Mol. Opt. Phys.}, volume = {39}, number = {10}, year = {2006}, pages = {S199{\textendash}S210}, abstract = {We report on the experimental demonstration of dynamic control of the motional state of atoms in a 2D double-well optical lattice. First we describe experiments in which the atomic distributions obtained by loading Bose{\textendash}Einstein condensates of rubidium atoms in the lattice are dynamically split by transforming a 2D lattice with period ${\l}ambda$ into a 2D lattice with period ${\l}ambda$/2, and we show how this procedure allows for the study of the coherence and interaction properties of the system. Then we show how we can efficiently adiabatically transfer the population between adjacent sites of the lattice, as well as between different energy bands, by using dynamic modifications of the potential.}, keywords = {2006, Multiple Fellows}, issn = {0953-4075}, url = {http://stacks.iop.org/0953-4075/39/i=10/a=S19}, author = {Anderlini, M. and Jennifer Sebby-Strabley and Kruse, Jens and J V Porto and William D Phillips} } @article {Tewari2006, title = {Emergence of Artificial Photons in an Optical Lattice}, journal = {Phys. Rev. Lett.}, volume = {97}, number = {20}, year = {2006}, month = {nov}, pages = {4}, abstract = {We establish the theoretical feasibility of direct analog simulation of the compact U(1) lattice gauge theories in optical lattices with dipolar bosons. We discuss the realizability of the topological Coulomb phase in extended Bose-Hubbard models in several optical lattice geometries. We predict the testable signatures of this emergent phase in noise correlation measurements, thus suggesting the possible emergence of artificial light in optical lattices.}, keywords = {2006, Single Fellow}, issn = {0031-9007}, url = {http://arxiv.org/abs/cond-mat/0605154}, author = {Tewari, Sumanta and V W Scarola and Senthil, T. and S. Das Sarma} } @article { ISI:000241238100001, title = {Emergent phenomena in quantum Hall systems}, journal = {SOLID STATE COMMUNICATIONS}, volume = {140}, number = {2, SI}, year = {2006}, month = {OCT}, pages = {51}, issn = {0038-1098}, doi = {10.1016/j.ssc.2006.08.001}, author = {S. Das Sarma and Eisenstein, Jim and Pellegrini, Vittorio and Simon, Steve} } @article {Tang2006, title = {Experimental study of high speed polarization-coding quantum key distribution with sifted-key rates over Mbit/s}, journal = {Optics Express}, volume = {14}, number = {6}, year = {2006}, pages = {2062}, publisher = {OSA}, abstract = {We present a quantitative study of various limitations on quantum cryptographic systems operating with sifted-key rates over Mbit/s. The dead time of silicon APDs not only limits the sifted-key rate but also causes correlation between the neighboring key bits. In addition to the well-known count-rate dependent timing jitter in avalanche photo-diode (APD), the faint laser sources, the vertical cavity surface emission lasers (VCSELs) in our system, also induce a significant amount of data-dependent timing jitter. Both the dead time and the data-dependent timing jitter are major limiting factors in designing QKD systems with sifted-key rates beyond Mbit/s.}, keywords = {2006, Fiber optics communications, Multiple Fellows, Optical communications, Photon counting, Quantum detectors}, issn = {1094-4087}, url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-14-6-2062}, author = {Tang, Xiao and Ma, Lijun and Mink, Alan and Nakassis, Anastase and Hai Xu and Hershman, Barry and Bienfang, Joshua C. and Su, David and Boisvert, Ronald F. and Charles W Clark and Carl J Williams} } @article {Safronova2006, title = {Frequency-dependent polarizabilities of alkali-metal atoms from ultraviolet through infrared spectral regions}, journal = {Phys. Rev. A}, volume = {73}, number = {2}, year = {2006}, month = {feb}, keywords = {2006, Single Fellow}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v73/i2/e022505}, author = {Marianna S Safronova and Arora, Bindiya and Charles W Clark} } @article {Palomaki2006, title = {Initializing the flux state of multiwell inductively isolated Josephson junction qubits}, journal = {Phys. Rev. B}, volume = {73}, number = {1}, year = {2006}, month = {jan}, keywords = {2006, Multiple Fellows}, issn = {1098-0121}, url = {http://prb.aps.org/abstract/PRB/v73/i1/e014520}, author = {T A Palomaki and S K Dutta and Hanhee Paik and Hai Xu and Matthews, J. and R M Lewis and R C Ramos and Kaushik Mitra and Philip R Johnson and Frederick W Strauch and Dragt, A. J. and Christopher J Lobb and Jeffrey R Anderson and F C Wellstood} } @article {Sebby-Strabley2006, title = {Lattice of double wells for manipulating pairs of cold atoms}, journal = {Phys. Rev. A}, volume = {73}, number = {3}, year = {2006}, month = {mar}, keywords = {2006, Single Fellow}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v73/i3/e033605}, author = {Jennifer Sebby-Strabley and Anderlini, M. and Jessen, P. and J V Porto} } @article {Satija2006, title = {Metal-Insulator Transition Revisited for Cold Atoms in Non-Abelian Gauge Potentials}, journal = {Phys. Rev. Lett.}, volume = {97}, number = {21}, year = {2006}, pages = {216401}, keywords = {2006, Single Fellow}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v97/i21/e216401}, author = {Indubala Satija and Dakin, Daniel and Charles W Clark} } @article {Castelletto2006, title = {Optimizing single-photon-source heralding efficiency and detection efficiency metrology at 1550 nm using periodically poled lithium niobate}, journal = {Metrologia}, volume = {43}, number = {2}, year = {2006}, pages = {S56{\textendash}S60}, keywords = {2006, Single Fellow}, issn = {0026-1394}, url = {http://www.mendeley.com/research/optimizing-singlephotonsource-heralding-efficiency-and-detection-efficiency-metrology-at-1550nm-using-periodically-poled-lithium-niobate/}, author = {Stefania A Castelletto and Ivo P Degiovanni and Valentina Schettini and Alan L Migdall} } @article {Rey2006, title = {Quantum coherence of Hard-Core-Bosons and Fermions: Extended, Glassy and Mott Phases}, journal = {J. Phys. B: At. Mol. Opt. Phys.}, volume = {-1}, number = {8}, year = {2006}, month = {may}, pages = {3004}, abstract = {Noise correlations, such as those observable in the time of flight images of a released cloud, are calculated for hard-core bosonic (HCBs) atoms. These second-order correlations are used to explore quantum coherence of strongly correlated bosons in the fermionized regime with and without external parabolic confinement. Our analysis points to distinctive new experimental signatures of the Mott phase. We also calculate noise correlations for the corresponding spin-1/2 XY model onto which the HCB system is standardly mapped. Our study shows important differences between the two systems due to the contribution of multiply occupied virtual states in HCBs. Such states do not exist in spin models. An interesting manifestation of such states is the breaking of particle{\textendash}hole symmetry in HCB systems.}, keywords = {2006, Single Fellow}, issn = {1367-2630}, url = {http://stacks.iop.org/0953-4075/39/i=10/a=S17 http://adsabs.harvard.edu/abs/2006APS..DMP.N3004R http://arxiv.org/abs/cond-mat/0604154}, author = {A M Rey and Indubala Satija and Charles W Clark} } @article {Deng2006, title = {Quantum Degenerate Exciton-Polaritons in Thermal Equilibrium}, journal = {Phys. Rev. Lett.}, volume = {97}, number = {14}, year = {2006}, month = {oct}, abstract = {We study the momentum distribution and relaxation dynamics of semiconductor microcavity polaritons by angle-resolved and time-resolved spectroscopy. Above a critical pump level, the thermalization time of polaritons at positive detunings becomes shorter than their lifetime, and the polaritons form a quantum degenerate Bose-Einstein distribution in thermal equilibrium with the lattice.}, keywords = {2006, Single Fellow}, issn = {0031-9007}, url = {http://arxiv.org/abs/cond-mat/0604394}, author = {Deng, Hui and Press, David and Stephan G{\"o}tzinger and Glenn S Solomon and Hey, Rudolf and Ploog, Klaus and Yoshihisa Yamamoto} } @article { ISI:000237949300007, title = {Searching for a supersolid in cold-atom optical lattices}, journal = {PHYSICAL REVIEW A}, volume = {73}, number = {5}, year = {2006}, month = {MAY}, issn = {1050-2947}, doi = {10.1103/PhysRevA.73.051601}, author = {Scarola, V. W. and Demler, E. and S. Das Sarma} } @article {Belyanin2006, title = {Superfluorescence from dense electron-hole plasmas in high magnetic fields}, journal = {J. Phys.: Conf. Ser.}, volume = {51}, number = {1}, year = {2006}, month = {nov}, pages = {403{\textendash}406}, abstract = {Cooperative spontaneous recombination (superfluorescence) of electron-hole plasmas in semiconductors has been a challenge to observe due to ultrafast decoherence. We argue that superfluorescence can be achieved in quantum-confined semiconductor systems and present experimental evidence for superfluorescence from high-density photoexcited electronhole plasmas in magnetized quantum wells. At a critical magnetic field strength and excitation fluence, we observe a clear transition in the band-edge photoluminescence from omnidirectional output to a randomly directed but highly collimated beam. Changes in the linewidth, carrier density, and magnetic field scaling of the emission spectra correlate precisely with the onset of random directionality and are consistent with cooperative recombination.}, keywords = {2006, Single Fellow}, issn = {1742-6588}, url = {http://stacks.iop.org/1742-6596/51/i=1/a=093}, author = {A A Belyanin and Jho, Y. D. and Wang, X. and Kono, J. and Reitze, D. H. and Wei, X and Glenn S Solomon} } @article {Stanescu2006, title = {Surface states, Friedel oscillations, and spin accumulation in p-doped semiconductors}, journal = {Phys. Rev. B}, volume = {74}, number = {20}, year = {2006}, month = {nov}, keywords = {2006, Single Fellow}, issn = {1098-0121}, url = {http://www.mendeley.com/research/surface-states-friedel-oscillations-spin-accumulation-pdoped-semiconductors/}, author = {Tudor D Stanescu and Victor M Galitski} }