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 {21526, title = {Observation of {Stark} many-body localization without disorder}, journal = {Nature}, volume = {599}, year = {2021}, pages = {393{\textendash}398}, abstract = {Thermalization is a ubiquitous process of statistical physics, in which a physical system reaches an equilibrium state that is defined by a few global properties such as temperature. Even in isolated quantum many-body systems, limited to reversible dynamics, thermalization typically prevails1. However, in these systems, there is another possibility: many-body localization (MBL) can result in preservation of a non-thermal state2,3. While disorder has long been considered an essential ingredient for this phenomenon, recent theoretical work has suggested that a quantum many-body system with a spatially increasing field{\textemdash}but no disorder{\textemdash}can also exhibit MBL4, resulting in {\textquoteleft}Stark MBL{\textquoteright}5. Here we realize Stark MBL in a trapped-ion quantum simulator and demonstrate its key properties: halting of thermalization and slow propagation of correlations. Tailoring the interactions between ionic spins in an effective field gradient, we directly observe their microscopic equilibration for a variety of initial states, and we apply single-site control to measure correlations between separate regions of the spin chain. Furthermore, by engineering a varying gradient, we create a disorder-free system with coexisting long-lived thermalized and non-thermal regions. The results demonstrate the unexpected generality of MBL, with implications about the fundamental requirements for thermalization and with potential uses in engineering long-lived non-equilibrium quantum matter.

}, issn = {1476-4687}, doi = {10.1038/s41586-021-03988-0}, url = {https://doi.org/10.1038/s41586-021-03988-0}, author = {Morong, W. and Liu, F. and Becker, P. and Collins, K. S. and Feng, L. and Kyprianidis, A. and Pagano, G. and You, T. and Gorshkov, A. V. and Monroe, C.} } @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 { WOS:000665681100001, title = {Optimal calibration of gates in trapped-ion quantum computers}, journal = {Quantum Sci. Technol.}, volume = {6}, number = {3}, year = {2021}, month = {JUL}, publisher = {IOP Publishing Ltd}, type = {Article}, abstract = {To harness the power of quantum computing, it is essential that a quantum computer provide maximal possible fidelity for a quantum circuit. To this end, much work has been done in the context of qubit routing or embedding, i.e., mapping circuit qubits to physical qubits based on gate performance metrics to optimize the fidelity of execution. Here, we take an alternative approach that leverages a unique capability of a trapped-ion quantum computer, i.e., the all-to-all qubit connectivity. We develop a method to determine a fixed number (budget) of quantum gates that, when calibrated, will maximize the fidelity of a batch of input quantum programs. This dynamic allocation of calibration resources on randomly accessible gates, determined using our heuristics, increases, for a wide range of calibration budget, the average fidelity from 70\% or lower to 90\% or higher for a typical batch of jobs on an 11-qubit device, in which the fidelity of calibrated and uncalibrated gates are taken to be 99\% and 90\%, respectively. Our heuristics are scalable, more than 2.5 orders of magnitude faster than a randomized method for synthetic benchmark circuits generated based on real-world use cases.}, keywords = {connectivity, fidelity optimization, gate calibrations}, issn = {2058-9565}, doi = {10.1088/2058-9565/abf718}, author = {Maksymov, Andrii and Niroula, Pradeep and Nam, Yunseong} } @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 { WOS:000646067200012, title = {Optimal measurement of field properties with quantum sensor networks}, journal = {Phys. Rev. A}, volume = {103}, number = {3}, year = {2021}, month = {MAR 29}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We consider a quantum sensor network of qubit sensors coupled to a field f (x; theta) analytically parameterized by the vector of parameters theta. The qubit sensors are fixed at positions x(1), ..., x(d). While the functional form of f (x; theta) is known, the parameters theta are not. We derive saturable bounds on the precision of measuring an arbitrary analytic function q(theta) of these parameters and construct the optimal protocols that achieve these bounds. Our results are obtained from a combination of techniques from quantum information theory and duality theorems for linear programming. They can be applied to many problems, including optimal placement of quantum sensors, field interpolation, and the measurement of functionals of parametrized fields.}, issn = {2469-9926}, doi = {10.1103/PhysRevA.103.L030601}, author = {Qian, Timothy and Bringewatt, Jacob and Boettcher, Igor and Bienias, Przemyslaw and Gorshkov, V, Alexey} } @article {brady_optimal_2021, title = {Optimal {Protocols} in {Quantum} {Annealing} and {Quantum} {Approximate} {Optimization} {Algorithm} {Problems}}, journal = {Phys. Rev. Lett.}, volume = {126}, number = {7}, year = {2021}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {feb}, abstract = {Quantum annealing (QA) and the quantum approximate optimization algorithm (QAOA) are two special cases of the following control problem: apply a combination of two Hamiltonians to minimize the energy of a quantum state. Which is more effective has remained unclear. Here we analytically apply the framework of optimal control theory to show that generically, given a fixed amount of time, the optimal procedure has the pulsed (or {\textquotedblleft}bang-bang{\textquotedblright}) structure of QAOA at the beginning and end but can have a smooth annealing structure in between. This is in contrast to previous works which have suggested that bang-bang (i.e., QAOA) protocols are ideal. To support this theoretical work, we carry out simulations of various transverse field Ising models, demonstrating that bang-anneal-bang protocols are more common. The general features identified here provide guideposts for the nascent experimental implementations of quantum optimization algorithms.

}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.126.070505}, author = {Brady, Lucas T. and Baldwin, Christopher L. and Bapat, Aniruddha and Kharkov, Yaroslav and Gorshkov, Alexey V} } @article {21211, title = {Optimal State Transfer and Entanglement Generation in Power-Law Interacting Systems}, journal = {Phys. Rev. X}, volume = {11}, year = {2021}, month = {Jul}, pages = {031016}, abstract = {We present an optimal protocol for encoding an unknown qubit state into a multiqubit Greenberger-Horne-Zeilinger-like state and, consequently, transferring quantum information in large systems exhibiting power-law (1/rα) interactions. For all power-law exponents\ α\ between\ d\ and\ 2d+1, where\ d\ is the dimension of the system, the protocol yields a polynomial speed-up for\ α\>2d\ and a superpolynomial speed-up for\ α<=2d, compared to the state of the art. For all\ α\>d, the protocol saturates the Lieb-Robinson bounds (up to subpolynomial corrections), thereby establishing the optimality of the protocol and the tightness of the bounds in this regime. The protocol has a wide range of applications, including in quantum sensing, quantum computing, and preparation of topologically ordered states. In addition, the protocol provides a lower bound on the gate count in digital simulations of power-law interacting systems.

}, keywords = {quantum algorithms, quantum computing}, doi = {10.1103/PhysRevX.11.031016}, url = {https://link.aps.org/doi/10.1103/PhysRevX.11.031016}, author = {Tran, Minh C. and Guo, Andrew Y. and Deshpande, Abhinav and Lucas, Andrew and Gorshkov, Alexey V.} } @article { WOS:000665821600002, title = {Optimal two-qubit circuits for universal fault-tolerant quantum computation}, journal = {npj Quantum Inform.}, volume = {7}, number = {1}, year = {2021}, month = {JUN 22}, publisher = {NATURE RESEARCH}, type = {Article}, abstract = {We study two-qubit circuits over the Clifford+CS gate set, which consists of the Clifford gates together with the controlled-phase gate CS = diag(1, 1, 1, i). The Clifford+CS gate set is universal for quantum computation and its elements can be implemented fault-tolerantly in most error-correcting schemes through magic state distillation. Since non-Clifford gates are typically more expensive to perform in a fault-tolerant manner, it is often desirable to construct circuits that use few CS gates. In the present paper, we introduce an efficient and optimal synthesis algorithm for two-qubit Clifford+CS operators. Our algorithm inputs a Clifford+CS operator U and outputs a Clifford+CS circuit for U, which uses the least possible number of CS gates. Because the algorithm is deterministic, the circuit it associates to a Clifford+CS operator can be viewed as a normal form for that operator. We give an explicit description of these normal forms and use this description to derive a worst-case lower bound of 5log(2)(1/epsilon)+O(1) on the number of CS gates required to epsilon-approximate elements of SU(4). Our work leverages a wide variety of mathematical tools that may find further applications in the study of fault-tolerant quantum circuits.}, doi = {10.1038/s41534-021-00424-z}, author = {Glaudell, Andrew N. and Ross, Neil J. and Taylor, Jacob M.} } @article { WOS:000729420900001, title = {Optimizing Stabilizer Parities for Improved Logical Qubit Memories}, journal = {Phys. Rev. Lett.}, volume = {127}, number = {24}, year = {2021}, month = {DEC 6}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We study variants of Shor{\textquoteright}s code that are adept at handling single-axis correlated idling errors, which are commonly observed in many quantum systems. By using the repetition code structure of the Shor{\textquoteright}s code basis states, we calculate the logical channel applied to the encoded information when subjected to coherent and correlated single qubit idling errors, followed by stabilizer measurement. Changing the signs of the stabilizer generators allows us to change how the coherent errors interfere, leading to a quantum error correcting code which performs as well as a classical repetition code of equivalent distance against these errors. We demonstrate a factor of 3.78 +/- 1.20 improvement of the logical T2{*} in a distance-3 logical qubit implemented on a trapped-ion quantum computer. Even-distance versions of our Shor-code variants are decoherence-free subspaces and fully robust to identical and independent coherent idling noise.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.127.240501}, author = {Debroy, Dripto M. and Egan, Laird and Noel, Crystal and Risinger, Andrew and Zhu, Daiwei and Biswas, Debopriyo and Cetina, Marko and Monroe, Chris and Brown, Kenneth R.} } @article {xie_observation_2020, title = {Observation of {Efimov} {Universality} across a {Nonuniversal} {Feshbach} {Resonance} in {K}-39}, journal = {Phys. Rev. Lett.}, volume = {125}, number = {24}, year = {2020}, note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article}, month = {dec}, abstract = {We study three-atom inelastic scattering in ultracold K-39 near a Feshbach resonance of intermediate coupling strength. The nonuniversal character of such resonance leads to an abnormally large Efimov absolute length scale and a relatively small effective range r(e), allowing the features of the 39 K Efimov spectrum to be better isolated from the short-range physics. Meticulous characterization of and correction for finite-temperature effects ensure high accuracy on the measurements of these features at large-magnitude scattering lengths. For a single Feshbach resonance, we unambiguously locate four distinct features in the Efimov structure. Three of these features form ratios that obey the Efimov universal scaling to within 10\%, while the fourth feature, occurring at a value of scattering length closest to r(e), instead deviates from the universal value.}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.125.243401}, author = {Xie, Xin and Van de Graaff, Michael J. and Chapurin, Roman and Frye, Matthew D. and Hutson, Jeremy M. and D{\textquoteright}Incao, Jose P. and Julienne, Paul S. and Ye, Jun and Cornell, Eric A.} } @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:000550690300003, title = {On-demand indistinguishable single photons from an efficient and pure source based on a Rydberg ensemble}, journal = {Optica}, volume = {7}, number = {7}, year = {2020}, month = {JUL 20}, pages = {813-819}, publisher = {OPTICAL SOC AMER}, type = {Article}, abstract = {Single photons coupled to atomic systems have shown to be a promising platform for developing quantum technologies. Yet a bright on-demand, highly pure, and highly indistinguishable single-photon source compatible with atomic platforms is lacking. In this work, we demonstrate such a source based on a strongly interacting Rydberg system. The large optical nonlinearities in a blockaded Rydberg ensemble convert coherent light into a single collective excitation that can be coherently retrieved as a quantum field. We simultaneously observe a fully single-mode (spectral, temporal, spatial, and polarization) efficiency up to 0.098(2), a detector-background-subtracted g((2))+5.0(1.6) x 10(-4), and indistinguishability of 0.980(7), at an average photon production rate of 1.18(2) x 10(4) s(-1), All of these make this system promising for scalable quantum information applications. Furthermore, we investigate the effects of contaminant Rydberg excitations on the source efficiency and observed single-mode efficiencies up to 0.18(2) for lower photon rates. Finally, recognizing that many quantum information protocols require a single photon in a fully single mode, we introduce metrics that take into account all degrees of freedom to benchmark the performance of on-demand sources. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement}, issn = {2334-2536}, doi = {10.1364/OPTICA.391485}, author = {Ornelas-Huerta, D. P. and Craddock, A. N. and Goldschmidt, E. A. and Hachtel, A. J. and Wang, Y. and Bienias, P. and Gorshkov, A. V. and Rolston, S. L. and Porto, J. V.} } @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 {ge_operational_2020, title = {Operational resource theory of nonclassicality via quantum metrology}, 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}, abstract = {The nonclassical properties of quantum states are of tremendous interest due to their potential applications in future technologies. It has recently been realized that the concept of a resource theory is a powerful approach to quantifying and understanding nonclassicality. To realize the potential of this approach, one must first find resource theoretic measures of nonclassicality that are operational, meaning that they also quantify the ability of quantum states to provide enhanced performance for specific tasks, such as precision sensing. Here we achieve a significant milestone in this endeavor by presenting such an operational resource theoretic measure. In addition to satisfying the requirements of a resource measure, it has the closest possible relationship to the quantum enhancement provided by a nonclassical state for measuring phase-space displacement: It is equal to this enhancement for pure states and has a tight upper bound on it for mixed states. We also show that a lower bound on this measure can be obtained experimentally using a simple Mach-Zehnder interferometer.}, doi = {10.1103/PhysRevResearch.2.023400}, author = {Ge, Wenchao and Jacobs, Kurt and Asiri, Saeed and Foss-Feig, Michael and Zubairy, M. Suhail} } @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:000538714300009, title = {Optical enhancement of superconductivity via targeted destruction of charge density waves}, journal = {Phys. Rev. B}, volume = {101}, number = {22}, year = {2020}, month = {JUN 8}, pages = {224506}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {It has been experimentally established that the occurrence of charge density waves is a common feature of various underdoped cuprate superconducting compounds. The observed states, which are often found in the form of bond density waves (BDWs), usually occur in a temperature regime immediately above the superconducting transition temperature. Motivated by recent optical experiments on superconducting materials, where it has been shown that optical irradiation can transiently improve the superconducting features, here we propose an approach for the enhancement of superconductivity by the targeted destruction of the BDW order which we expect to be more efficient than the previous methods. Since BDW states are usually found in competition with superconductivity, suppression of the BDW order enhances the tendency of electrons to form Cooper pairs after reaching a steady state. By investigating the optical coupling of gapless, collective fluctuations of the BDW modes, we argue that the resonant excitation of these modes can melt the underlying BDW order parameter. We propose an experimental setup to implement such an optical coupling using two-dimensional plasmon-polariton hybrid systems.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.101.224506}, author = {Dehghani, Hossein and Raines, Zachary M. and Galitski, Victor M. and Hafezi, Mohammad} } @article { ISI:000527498000001, title = {Optical excitations in compressible and incompressible two-dimensional electron liquids}, journal = {Phys. Rev. B}, volume = {101}, number = {15}, year = {2020}, month = {APR 22}, pages = {155127}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Optically generated electron-hole pairs can probe strongly correlated electronic matter, or, by forming exciton-polaritons within an optical cavity, give rise to photonic nonlinearities. The present paper theoretically studies the properties of electron-hole pairs in a two-dimensional electron liquid in the fractional quantum Hall regime. In particular, we quantify the effective interactions between optical excitations by numerically evaluating the system{\textquoteright}s energy spectrum under the assumption of full spin and Landau level polarization. Optically most active are those pair excitations which do not modify the correlations of the electron liquid, also known as multiplicative states. In the case of spatial separation of electrons and holes, these excitations interact repulsively with each other. However, when the electron liquid is compressible, other nonmultiplicative configurations occur at lower energies. The interactions of such dark excitations strongly depend on the liquid, and can also become attractive. For the case of a single excitation, we also study the effect of Landau level mixing in the valence band which can dramatically change the effective mass of an exciton.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.101.155127}, author = {Grass, Tobias and Cotlet, Ovidiu and Imamoglu, Atac and Hafezi, Mohammad} } @article {kim_optical_2020, title = {Optical imprinting of superlattices in two-dimensional materials}, 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 = {oct}, abstract = {We propose an optical method of shining circularly polarized and spatially periodic laser fields to imprint superlattice structures in two-dimensional electronic systems. By changing the configuration of the optical field, we synthesize various lattice structures with different spatial symmetry, periodicity, and strength. We find that the wide optical tunability allows one to tune different properties of the effective band structure, including Chern number, energy bandwidths, and band gaps. The in situ tunability of the superlattice gives rise to unique physics ranging from the topological transitions to the creation of the flat bands through the kagome superlattice, which can allow a realization of strongly correlated phenomena in Floquet systems. We consider the high-frequency regime where the electronic system can remain in the quasiequilibrium phase for an extended amount of time. The spatiotemporal reconfigurability of the present scheme opens up possibilities to control light-matter interaction to generate novel electronic states and optoelectronic devices.}, doi = {10.1103/PhysRevResearch.2.043004}, author = {Kim, Hwanmun and Dehghani, Hossein and Aoki, Hideo and Martin, Ivar and Hafezi, Mohammad} } @article {ISI:000455320600043, title = {Observation of chiral zero mode in inhomogeneous three-dimensional Weyl metamaterials}, journal = {Science}, volume = {363}, number = {6423}, year = {2019}, month = {JAN 11}, pages = {148-151}, publisher = {AMER ASSOC ADVANCEMENT SCIENCE}, type = {Article}, abstract = {Owing to the chirality of Weyl nodes, the Weyl systems can support one-way chiral zero modes under a strong magnetic field, which leads to nonconservation of chiral currents-the so-called chiral anomaly. Although promising for robust transport of optical information, the zero chiral bulk modes have not been observed in photonics. Here we design an inhomogeneous Weyl metamaterial in which a gauge field is generated for the Weyl nodes by engineering the individual unit cells. We experimentally confirm the presence of the gauge field and observe the zero-order chiral Landau level with one-way propagation. Without breaking the time-reversal symmetry, our system provides a route for designing an artificial magnetic field in three-dimensional photonic Weyl systems and may have potential for device applications in photonics.}, issn = {0036-8075}, doi = {10.1126/science.aau7707}, author = {Jia, Hongwei and Zhang, Ruixing and Gao, Wenlong and Guo, Qinghua and Yang, Biao and Hu, Jing and Bi, Yangang and Xiang, Yuanjiang and Liu, Chaoxing and Zhang, Shuang} } @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 {ISI:000462898900011, title = {Optical response of Luttinger semimetals in the normal and superconducting states}, journal = {Phys. Rev. B}, volume = {99}, number = {12}, year = {2019}, month = {MAR 25}, pages = {125146}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {We investigate the optical response properties of three-dimensional Luttinger semimetals with the Fermi energy close to a quadratic band touching point. In particular, in order to address recent experiments on the spectroscopy of pyrochlore iridates and half-Heusler superconductors, we derive expressions for the optical conductivity in both the normal and general superconducting states in the linear response regime within the random phase approximation. The response functions can be decomposed into contributions from intraband and interband transitions, the latter comprising a genuine signature of the quadratic band touching point. We demonstrate the importance of interband transitions in the optical response in the normal state both in the homogeneous and quasistatic limit. Our analysis reveals a factorization property of the homogeneous conductivity in the spatially anisotropic case and the divergence of the conductivity for strong spatial anisotropy. In the quasistatic limit, the response is dominated by interband transitions and significantly different from systems with a single parabolic band. As an applications of the formalism in the superconducting state we compute the optical conductivity and superfluid density for the s-wave singlet superconducting case for both finite and vanishing chemical potential.}, issn = {2469-9950}, doi = {10.1103/PhysRevB.99.125146}, author = {Boettcher, Igor} } @article {ISI:000473132200039, title = {Orbital-flop Induced Magnetoresistance Anisotropy in Rare Earth Monopnictide CeSb}, journal = {Nat. Commun.}, volume = {10}, year = {2019}, month = {JUN 28}, pages = {2875}, publisher = {NATURE PUBLISHING GROUP}, type = {Article}, abstract = {The charge and spin of the electrons in solids have been extensively exploited in electronic devices and in the development of spintronics. Another attribute of electrons-their orbital nature-is attracting growing interest for understanding exotic phenomena and in creating the next-generation of quantum devices such as orbital qubits. Here, we report on orbital-flop induced magnetoresistance anisotropy in CeSb. In the low temperature high magnetic-field driven ferromagnetic state, a series of additional minima appear in the angle-dependent magnetoresistance. These minima arise from the anisotropic magnetization originating from orbital-flops and from the enhanced electron scattering from magnetic multidomains formed around the first-order orbital-flop transition. The measured magnetization anisotropy can be accounted for with a phenomenological model involving orbital-flops and a spin-valve-like structure is used to demonstrate the viable utilization of orbital-flop phenomenon. Our results showcase a contribution of orbital behavior in the emergence of intriguing phenomena.}, issn = {2041-1723}, doi = {10.1038/s41467-019-10624-z}, author = {Xu, Jing and Wu, Fengcheng and Bao, Jin-Ke and Han, Fei and Xiao, Zhi-Li and Martin, Ivar and Lyu, Yang-Yang and Wang, Yong-Lei and Chung, Duck Young and Li, Mingda and Zhang, Wei and Pearson, John E. and Jiang, Jidong S. and Kanatzidis, Mercouri G. and Kwok, Wai-Kwong} } @article {ISI:000456825600004, title = {Origin of spectral brightness variations in InAs/InP quantum dot telecom single photon emitters}, journal = {J. Vac. Sci. Technol. B}, volume = {37}, number = {1}, year = {2019}, month = {JAN}, pages = {011202}, publisher = {A V S AMER INST PHYSICS}, type = {Article}, abstract = {Long-distance quantum communication relies on the ability to efficiently generate and prepare single photons at telecom wavelengths. Low-density InAs quantum dots on InP surfaces are grown in a molecular beam epitaxy system using a modified Stranski-Krastanov growth paradigm. This material is a source of bright and indistinguishable single photons in the 1.3 mu m telecom band. Here, the exploration of the growth parameters is presented as a phase diagram, while low-temperature photoluminescence and atomic resolution images are presented to correlate structure and spectral performance. This work identifies specific stacking faults and V-shaped defects that are likely causes of the observed low brightness emission at 1.55 mu m telecom wavelengths. The different locations of the imaged defects suggest possible guidance for future development of InAs/InP single photon sources for c-band, 1.55 mu m wavelength telecommunication systems.}, issn = {1071-1023}, doi = {10.1116/1.5042540}, author = {Richardson, Christopher J. K. and Leavitt, Richard P. and Kim, Je-Hyung and Waks, Edo and Arslan, Ilke and Arey, Bruce} } @article { ISI:000450584900008, title = {Observation of bound state self-interaction in a nano-eV atom collider}, journal = {NATURE COMMUNICATIONS}, volume = {9}, year = {2018}, month = {NOV 20}, pages = {4895}, issn = {2041-1723}, doi = {10.1038/s41467-018-07375-8}, author = {Thomas, Ryan and Chilcott, Matthew and Tiesinga, Eite and Deb, Amita B. and Kjaergaard, Niels} } @article {ISI:000424750200005, title = {Observation of Hopping and Blockade of Bosons in a Trapped Ion Spin Chain}, journal = {PHYSICAL REVIEW LETTERS}, volume = {120}, number = {7}, year = {2018}, month = {FEB 12}, pages = {073001}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {The local phonon modes in a Coulomb crystal of trapped ions can represent a Hubbard system of coupled bosons. We selectively prepare single excitations at each site and observe free hopping of a boson between sites, mediated by the long-range Coulomb interaction between ions. We then implement phonon blockades on targeted sites by driving a Jaynes-Cummings interaction on individually \%\%Addressed ions to couple their internal spin to the local phonon mode. The resulting dressed states have energy splittings that can be tuned to suppress phonon hopping into the site. This new experimental approach opens up the possibility of realizing large-scale Hubbard systems from the bottom up with tunable interactions at the single-site level.}, \%\%Address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.120.073001}, author = {Debnath, S. and Linke, N. M. and Wang, S. -T. and Figgatt, C. and Landsman, K. A. and Duan, L. -M. and Monroe, C.} } @article {ISI:000425116200042, title = {Observation of three-photon bound states in a quantum nonlinear medium}, journal = {SCIENCE}, volume = {359}, number = {6377}, year = {2018}, month = {FEB 16}, pages = {783-786}, publisher = {AMER ASSOC ADVANCEMENT SCIENCE}, type = {Article}, abstract = {Bound states of massive particles, such as nuclei, atoms, or molecules, constitute the bulk of the visible world around us. By contrast, photons typically only interact weakly. We report the observation of traveling three-photon bound states in a quantum nonlinear medium where the interactions between photons are mediated by atomic Rydberg states. Photon correlation and conditional phase measurements reveal the distinct bunching and phase features associated with three-photon and two-photon bound states. Such photonic trimers and dimers possess shape-preserving wave functions that depend on the constituent photon number. The observed bunching and strongly nonlinear optical phase are described by an effective field theory of Rydberg-induced photon-photon interactions. These observations demonstrate the ability to realize and control strongly interacting quantum many-body states of light.}, \%Address = {1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA}, issn = {0036-8075}, doi = {10.1126/science.aao7293}, author = {Liang, Qi-Yu and Venkatramani, Aditya V. and Cantu, Sergio H. and Nicholson, Travis L. and Gullans, Michael J. and Gorshkov, Alexey V. and Thompson, Jeff D. and Chin, Cheng and Lukin, Mikhail D. and Vuletic, Vladan} } @article { ISI:000447918000006, title = {Odd-frequency pairing in the edge states of superconducting pnictides in the coexistence phase with antiferromagnetism}, journal = {PHYSICAL REVIEW B}, volume = {98}, number = {14}, year = {2018}, month = {OCT 22}, pages = {144517}, issn = {2469-9950}, doi = {10.1103/PhysRevB.98.144517}, author = {Youmans, Cody and Ghazaryan, Areg and Kargarian, Mehdi and Ghaemi, Pouyan} } @article { ISI:000447301700001, title = {Optical control over bulk excitations in fractional quantum Hall systems}, journal = {PHYSICAL REVIEW B}, volume = {98}, number = {15}, year = {2018}, month = {OCT 15}, pages = {155124}, issn = {2469-9950}, doi = {10.1103/PhysRevB.98.155124}, author = {Grass, Tobias and Gullans, Michael and Bienias, Przemyslaw and Zhu, Guanyu and Ghazaryan, Areg and Ghaemi, Pouyan and Hafezi, Mohammad} } @article { ISI:000445733100006, title = {Optical Lattice with Torus Topology}, journal = {PHYSICAL REVIEW LETTERS}, volume = {121}, number = {13}, year = {2018}, month = {SEP 26}, pages = {133002}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.121.133002}, author = {Kim, Hwanmun and Zhu, Guanyu and Porto, V, J. and Hafezi, Mohammad} } @article {ISI:000430543700006, title = {Optimal and secure measurement protocols for quantum sensor networks}, journal = {PHYSICAL REVIEW A}, volume = {97}, number = {4}, year = {2018}, month = {APR 23}, pages = {042337}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Studies of quantum metrology have shown that the use of many-body entangled states can lead to an enhancement in sensitivity when compared with unentangled states. In this paper, we quantify the metrological advantage of entanglement in a setting where the measured quantity is a linear function of parameters individually coupled to each qubit. We first generalize the Heisenberg limit to the measurement of nonlocal observables in a quantum network, deriving a bound based on the multiparameter quantum Fisher information. We then propose measurement protocols that can make use of Greenberger-Horne-Zeilinger (GHZ) states or spin-squeezed states and show that in the case of GHZ states the protocol is optimal, i.e., it saturates our bound. We also identify nanoscale magnetic resonance imaging as a promising setting for this technology.}, \%\%Address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA}, issn = {2469-9926}, doi = {10.1103/PhysRevA.97.042337}, author = {Eldredge, Zachary and Foss-Feig, Michael and Gross, Jonathan A. and Rolston, S. L. and Gorshkov, Alexey V.} } @article { ISI:000443327900004, title = {Optimization of photon storage fidelity in ordered atomic arrays}, journal = {NEW JOURNAL OF PHYSICS}, volume = {20}, year = {2018}, month = {AUG 31}, pages = {083048}, keywords = {atomic ensembles, quantum memory, subradiance, superradiance}, issn = {1367-2630}, doi = {10.1088/1367-2630/aadb74}, author = {Manzoni, M. T. and Moreno-Cardoner, M. and Asenjo-Garcia, A. and Porto, J. V. and Gorshkov, A. V. and Chang, D. 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:000428647300012, title = {Optomechanical approach to controlling the temperature and chemical potential of light}, journal = {PHYSICAL REVIEW A}, volume = {97}, number = {3}, year = {2018}, month = {MAR 29}, pages = {033850}, publisher = {AMER PHYSICAL SOC}, type = {Article}, abstract = {Massless particles, including photons, are not governed by particle conservation law during their typical interaction with matter even at low energies and thus have no chemical potential. However, in driven systems, near-equilibrium dynamics can lead to equilibration of photons with a finite number, describable using an effective chemical potential {[}M. Hafezi et al., Phys. Rev. B 92, 174305 (2015)]. Here we build upon this general concept with an implementation appropriate for a photon-based quantum simulator. We consider how laser cooling of a well-isolated mechanical mode can provide an effective low-frequency bath for the quantum simulator system. We show that the use of auxiliary photon modes, coupled by the mechanical system, enables control of both the chemical potential and temperature of the resulting photonic quantum simulator{\textquoteright}s grand canonical ensemble.}, \%\%Address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA}, issn = {2469-9926}, doi = {10.1103/PhysRevA.97.033850}, author = {Wang, Chiao-Hsuan and Taylor, Jacob M.} } @article { ISI:000433905200011, title = {Orbital quantum magnetism in spin dynamics of strongly interacting magnetic lanthanide atoms}, journal = {PHYSICAL REVIEW A}, volume = {97}, number = {5}, year = {2018}, month = {MAY 31}, pages = {053627}, issn = {2469-9926}, doi = {10.1103/PhysRevA.97.053627}, author = {Li, Ming and Tiesinga, Eite and Kotochigova, Svetlana} } @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 {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 {7821, title = {Observation of a many-body dynamical phase transition with a 53-qubit quantum simulator}, journal = {Nature}, volume = {551}, year = {2017}, chapter = {601}, author = {J Zhang and G Pagano and P. W. Hess and A Kyprianidis and P. Becker and H. Kaplan and A. V. Gorshkov and Gong, Z-X and Christopher Monroe} } @article {ISI:000395052200001, title = {Observation of optomechanical buckling transitions}, journal = {NATURE COMMUNICATIONS}, volume = {8}, year = {2017}, month = {MAR 1}, pages = {14481}, abstract = {Correlated phases of matter provide long-term stability for systems as diverse as solids, magnets and potential exotic quantum materials. Mechanical systems, such as buckling transition spring switches, can have engineered, stable configurations whose dependence on a control variable is reminiscent of non-equilibrium phase transitions. In hybrid optomechanical systems, light and matter are strongly coupled, allowing engineering of rapid changes in the force landscape, storing and processing information, and ultimately probing and controlling behaviour at the quantum level. Here we report the observation of first-and second-order buckling transitions between stable mechanical states in an optomechanical system, in which full control of the nature of the transition is obtained by means of the laser power and detuning. The underlying multiwell confining potential we create is highly tunable, with a sub-nanometre distance between potential wells. Our results enable new applications in photonics and information technology, and may enable explorations of quantum phase transitions and macroscopic quantum tunnelling in mechanical systems.}, issn = {2041-1723}, doi = {10.1038/ncomms14481}, author = {Xu, H. and Kemiktarak, U. and Fan, J. and Ragole, S. and Lawall, J. and Taylor, J. M.} } @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} } @article {ISI:000403271700004, title = {Observation of Topological Links Associated with Hopf Insulators in a Solid-State Quantum Simulator}, journal = {CHINESE PHYSICS LETTERS}, volume = {34}, number = {6}, year = {2017}, month = {JUN}, pages = {060302}, publisher = {IOP PUBLISHING LTD}, type = {Article}, abstract = {Hopf insulators are intriguing three-dimensional topological insulators characterized by an integer topological invariant. They originate from the mathematical theory of Hopf fibration and epitomize the deep connection between knot theory and topological phases of matter, which distinguishes them from other classes of topological insulators. Here, we implement a model Hamiltonian for Hopf insulators in a solid-state quantum simulator and report the first experimental observation of their topological properties, including nontrivial topological links associated with the Hopf fibration and the integer-valued topological invariant obtained from a direct tomographic measurement. Our observation of topological links and Hopf fibration in a quantum simulator opens the door to probe rich topological properties of Hopf insulators in experiments. The quantum simulation and probing methods are also applicable to the study of other intricate three-dimensional topological model Hamiltonians.}, \%\%Address = {TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND}, issn = {0256-307X}, doi = {10.1088/0256-307X/34/6/060302}, author = {Yuan, X. -X. and He, L. and Wang, S. -T. and Deng, D. -L. and Wang, F. and Lian, W. -Q. and Wang, X. and Zhang, C. -H. and Zhang, H. -L. and Chang, X. -Y. and Duan, L. -M.} } @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:000359984400001, title = {Observation of an unexpected negative isotope shift in Th-229(+) and its theoretical explanation}, journal = {PHYSICAL REVIEW A}, volume = {92}, number = {2}, year = {2015}, month = {AUG 25}, issn = {1050-2947}, doi = {10.1103/PhysRevA.92.020503}, author = {Okhapkin, M. V. and Meier, D. M. and Peik, E. and Safronova, M. S. and Kozlov, M. G. and Porsev, S. G.} } @conference { ISI:000359481900003, title = {On-Chip Silicon Photonic Thermometers: from Waveguide Bragg Grating to Ring Resonators sensors}, booktitle = {ADVANCED ENVIRONMENTAL, CHEMICAL, AND BIOLOGICAL SENSING TECHNOLOGIES XII}, series = {Proceedings of SPIE}, volume = {9486}, year = {2015}, note = {Conference on Advanced Environmental, Chemical, and Biological Sensing Technologies XII, Baltimore, MD, APR 20-21, 2015}, isbn = {978-1-62841-602-2}, issn = {0277-786X}, doi = {10.1117/12.2176666}, author = {Klimov, Nikolai N. and Purdy, Thomas and Ahmed, Zeeshan}, editor = {VoDinh, T and Lieberman, RA and Gauglitz, GG} } @article { ISI:000360810200003, title = {On-chip silicon waveguide Bragg grating photonic temperature sensor}, journal = {OPTICS LETTERS}, volume = {40}, number = {17}, year = {2015}, month = {SEP 1}, pages = {3934-3936}, issn = {0146-9592}, doi = {10.1364/OL.40.003934}, author = {Klimov, Nikolai N. and Mittal, Sunil and Berger, Michaela and Ahmed, Zeeshan} } @article { ISI:000362891800003, title = {Optical activity as a test for dynamic chiral magnetic effect of Weyl semimetals}, journal = {PHYSICAL REVIEW B}, volume = {92}, number = {16}, year = {2015}, month = {OCT 12}, issn = {1098-0121}, doi = {10.1103/PhysRevB.92.161110}, author = {Goswami, Pallab and Sharma, Girish and Tewari, Sumanta} } @article { ISI:000364407400005, title = {Optical control of donor spin qubits in silicon}, journal = {PHYSICAL REVIEW B}, volume = {92}, number = {19}, year = {2015}, month = {NOV 11}, pages = {195411}, issn = {1098-0121}, doi = {10.1103/PhysRevB.92.195411}, author = {Gullans, M. J. and Taylor, J. M.} } @article { ISI:000366495700001, title = {Optical evidence for a Weyl semimetal state in pyrochlore Eu2Ir2O7}, journal = {PHYSICAL REVIEW B}, volume = {92}, number = {24}, year = {2015}, month = {DEC 14}, issn = {1098-0121}, doi = {10.1103/PhysRevB.92.241108}, author = {Sushkov, A. B. and Hofmann, J. B. and Jenkins, G. S. and Ishikawa, J. and Nakatsuji, S. and S. Das Sarma and Drew, H. D.} } @article { ISI:000359938200016, title = {Optical Feshbach resonances: Field-dressed theory and comparison with experiments}, journal = {PHYSICAL REVIEW A}, volume = {92}, number = {2}, year = {2015}, month = {AUG 24}, issn = {1050-2947}, doi = {10.1103/PhysRevA.92.022709}, author = {Nicholson, T. L. and Blatt, S. and Bloom, B. J. and James R. Williams and Thomsen, J. W. and Ye, J. and Julienne, Paul S.} } @article { ISI:000360415400009, title = {Optical Signatures of Quantum Delocalization over Extended Domains in Photosynthetic Membranes}, journal = {JOURNAL OF PHYSICAL CHEMISTRY A}, volume = {119}, number = {34}, year = {2015}, month = {AUG 27}, pages = {9043-9050}, issn = {1089-5639}, doi = {10.1021/acs.jpca.5b04804}, author = {Schroeder, Christopher A. and Caycedo-Soler, Felipe and Huelga, Susana F. and Plenio, Martin B.} } @article { ISI:000367378900014, title = {Optical spin readout method in a quantum dot using the ac Stark effect}, journal = {PHYSICAL REVIEW B}, volume = {92}, number = {24}, year = {2015}, month = {DEC 28}, pages = {245309}, issn = {1098-0121}, doi = {10.1103/PhysRevB.92.245309}, author = {Flagg, Edward B. and Solomon, Glenn S.} } @article { ISI:000367018100001, title = {Optimal excitation conditions for indistinguishable photons from quantum dots}, journal = {NEW JOURNAL OF PHYSICS}, volume = {17}, year = {2015}, month = {DEC 18}, pages = {123025}, issn = {1367-2630}, doi = {10.1088/1367-2630/17/12/123025}, author = {Huber, Tobias and Predojevic, Ana and Foeger, Daniel and Solomon, Glenn and Weihs, Gregor} } @article { ISI:000353121400006, title = {Optimization of collisional Feshbach cooling of an ultracold nondegenerate gas}, journal = {PHYSICAL REVIEW A}, volume = {91}, number = {4}, year = {2015}, month = {APR 20}, issn = {1050-2947}, doi = {10.1103/PhysRevA.91.043626}, author = {Nuske, Marlon and Tiesinga, Eite and Mathey, L.} } @article { ISI:000362491400023, title = {Optomechanical reference accelerometer}, journal = {METROLOGIA}, volume = {52}, number = {5}, year = {2015}, month = {OCT}, pages = {654-665}, issn = {0026-1394}, doi = {10.1088/0026-1394/52/5/654}, author = {Gerberding, O. and Cervantes, F. Guzman and Melcher, J. and Pratt, J. R. and Taylor, J. M.} } @article { ISI:000343242700017, title = {Observation of coherence oscillations of single ensemble excitations in methanol}, journal = {JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS}, volume = {31}, number = {9}, year = {2014}, month = {SEP}, pages = {2131-2135}, issn = {0740-3224}, doi = {10.1364/JOSAB.31.002131}, author = {Meiselman, Seth and Cohen, Offir and DeCamp, Matthew F. and Lorenz, Virginia O.} } @article { ISI:000345422200008, title = {Odd-parity superconductivity from phonon-mediated pairing: Application to CuxBi2Se3}, journal = {PHYSICAL REVIEW B}, volume = {90}, number = {18}, year = {2014}, month = {NOV 14}, issn = {1098-0121}, doi = {10.1103/PhysRevB.90.184512}, author = {Brydon, P. M. R. and S. Das Sarma and Hui, Hoi-Yin and Sau, Jay D.} } @article { ISI:000345858500056, title = {Offline trapping of Fr-221 in a magneto-optical trap from implantation of an Ac-225 ion beam}, journal = {JOURNAL OF INSTRUMENTATION}, volume = {9}, year = {2014}, month = {OCT}, issn = {1748-0221}, doi = {10.1088/1748-0221/9/10/P10013}, author = {Tandeck, M. and Zhang, J. and Aubin, S. and Behr, J. A. and Collister, R. and Gomez, E. and Gwinner, G. and Heggen, H. and Lassen, J. and Orozco, L. A. and Pearson, M. R. and Raeder, S. and Teigelhoefer, A.} } @article { ISI:000332224400046, title = {Optical detection of radio waves through a nanomechanical transducer}, journal = {NATURE}, volume = {507}, number = {7490}, year = {2014}, month = {MAR 6}, pages = {81-85}, issn = {0028-0836}, doi = {10.1038/nature13029}, author = {Bagci, T. and Simonsen, A. and Schmid, S. and Villanueva, L. G. and Zeuthen, E. and J. Appel and Taylor, J. M. and Sorensen, A. and Usami, K. and Schliesser, A. and Polzik, E. S.} } @article {2396, title = {An optical lattice clock with accuracy and stability at the 10^-18 level}, journal = {Nature}, volume = {506}, year = {2014}, month = {1/2014}, pages = {71-75}, doi = {10.1038/nature12941}, author = {Bloom, B. and T L Nicholson and James R. Williams and S. L. Campbell and M. Bishof and X. Zhang and W. Zhang and S. L. Bromley and Jun Ye} } @article { ISI:000335928800002, title = {Optimal Quantum Control of Multimode Couplings between Trapped Ion Qubits for Scalable Entanglement}, journal = {PHYSICAL REVIEW LETTERS}, volume = {112}, number = {19}, year = {2014}, month = {MAY 14}, issn = {0031-9007}, doi = {10.1103/PhysRevLett.112.190502}, author = {Choi, T. and Debnath, S. and Manning, T. A. and Figgatt, C. and Gong, Z. -X. and Duan, L. -M. and C. Monroe} } @article { ISI:000331217300011, title = {Optimally focused cold atom systems obtained using density-density correlations}, journal = {REVIEW OF SCIENTIFIC INSTRUMENTS}, volume = {85}, number = {1}, year = {2014}, month = {JAN}, issn = {0034-6748}, doi = {10.1063/1.4862046}, author = {Andika Putra and Daniel L Campbell and Ryan M. Price and Subhadeep De and Ian B Spielman} } @article { ISI:000332518100085, title = {Overcoming Auger recombination in nanocrystal quantum dot laser using spontaneous emission enhancement}, journal = {OPTICS EXPRESS}, volume = {22}, number = {3}, year = {2014}, month = {FEB 10}, pages = {3013-3027}, issn = {1094-4087}, doi = {10.1364/OE.22.003013}, author = {Shilpi Gupta 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.} } @article { ISI:000317963700006, title = {Oscillator-field model of moving mirrors in quantum optomechanics}, journal = {Phys. Rev. A}, volume = {87}, number = {4}, year = {2013}, month = {APR 24}, issn = {1050-2947}, doi = {10.1103/PhysRevA.87.043832}, author = {Galley, Chad R. and Ryan O Behunin and Bei-Lok Hu} } @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:000311320100013, title = {Optical logic gates using coherent feedback}, journal = {APPLIED PHYSICS LETTERS}, volume = {101}, number = {19}, year = {2012}, month = {NOV 5}, issn = {0003-6951}, doi = {10.1063/1.4767133}, author = {Zhou, Zhifan and Liu, Cunjin and Fang, Yami and Zhou, Jun and Glasser, Ryan T. and Chen, Liqing and Jing, Jietai and Zhang, Weiping} } @article { ISI:000306993000001, title = {Optical manifestations of symmetry breaking in bilayer graphene}, journal = {PHYSICAL REVIEW B}, volume = {86}, number = {4}, year = {2012}, month = {JUL 31}, issn = {1098-0121}, doi = {10.1103/PhysRevB.86.041410}, author = {Abergel, D. S. L. and Fal{\textquoteright}ko, Vladimir I.} } @article { ISI:000307717200005, title = {Optimized multichannel quantum defect theory for cold molecular collisions}, journal = {PHYSICAL REVIEW A}, volume = {86}, number = {2}, year = {2012}, month = {AUG 20}, issn = {1050-2947}, doi = {10.1103/PhysRevA.86.022711}, author = {Croft, James F. E. and Hutson, Jeremy M. and Julienne, Paul S.} } @article {Hafezi2012a, title = {Optomechanically induced non-reciprocity in microring resonators}, journal = {Optics Express}, volume = {20}, number = {7}, year = {2012}, month = {mar}, pages = {7672}, publisher = {OSA}, abstract = {We describe a new approach for on-chip optical non-reciprocity which makes use of strong optomechanical interaction in microring resonators. By optically pumping the ring resonator in one direction, the optomechanical coupling is only enhanced in that direction, and consequently, the system exhibits a non-reciprocal response. For different configurations, this system can function either as an optical isolator or a coherent non-reciprocal phase shifter. We show that the operation of such a device on the level of single-photon could be achieved with existing technology.

}, keywords = {Coherent optical effects, Isolators, No Fellows, Optomechanics}, issn = {1094-4087}, url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-20-7-7672}, author = {Mohammad Hafezi and Rabl, Peter} } @article {Barnett2012, title = {Order by disorder in spin-orbit-coupled Bose-Einstein condensates}, journal = {Phys. Rev. A}, volume = {85}, number = {2}, year = {2012}, month = {feb}, pages = {023615}, keywords = {Single Fellow}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v85/i2/e023615}, author = {Ryan Barnett and Powell, Stephen and Gra{\ss}, Tobias and Maciej Lewenstein 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 {Islam2011, title = {Onset of a quantum phase transition with a trapped ion quantum simulator}, journal = {Nat. Comm.}, volume = {2}, year = {2011}, month = {jan}, pages = {377}, publisher = {Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.}, abstract = {A quantum simulator is a well-controlled quantum system that can follow the evolution of a prescribed model whose behaviour may be difficult to determine. A good example is the simulation of a set of interacting spins, where phase transitions between various spin orders can underlie poorly understood concepts such as spin liquids. Here we simulate the emergence of magnetism by implementing a fully connected non-uniform ferromagnetic quantum Ising model using up to 9 trapped (171)Yb(+) ions. By increasing the Ising coupling strengths compared with the transverse field, the crossover from paramagnetism to ferromagnetic order sharpens as the system is scaled up, prefacing the expected quantum phase transition in the thermodynamic limit. We measure scalable order parameters appropriate for large systems, such as various moments of the magnetization. As the results are theoretically tractable, this work provides a critical benchmark for the simulation of intractable arbitrary fully connected Ising models in larger systems.}, keywords = {2011, Computer Simulation, Fluorescence, Isotopes, Isotopes: chemistry, Magnetics, Models, Monte Carlo Method, Multiple JQI Affil., Phase Transition, Quantum Theory, Single Fellow, Theoretical, Thermodynamics, Ytterbium, Ytterbium: chemistry}, issn = {2041-1723}, url = {http://arxiv.org/abs/1103.2400 http://dx.doi.org/10.1038/ncomms1374}, author = {Rajibul Islam and Emily E Edwards and K Kim and Simcha Korenblit and Noh, C and Howard J Carmichael and G -D Lin and L M Duan and C C J Wang and J K Freericks and Christopher Monroe} } @article { ISI:000292925300003, title = {Optical and transport gaps in gated bilayer graphene}, journal = {PHYSICAL REVIEW B}, volume = {84}, number = {4}, year = {2011}, month = {JUL 20}, issn = {1098-0121}, doi = {10.1103/PhysRevB.84.041406}, author = {Min, Hongki and Abergel, D. S. L. and Hwang, E. H. and S. Das Sarma} } @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 { 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 {Clade2009, title = {Observation of a 2D Bose Gas: From Thermal to Quasicondensate to Superfluid}, journal = {Phys. Rev. Lett.}, volume = {102}, number = {17}, year = {2009}, month = {apr}, keywords = {2009}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v102/i17/e170401}, author = {Pierre Clad{\'e} and Changhyun Ryu and Anand Ramanathan and Kristian Helmerson and William D Phillips} } @article {Malkova2009a, title = {Observation of optical Shockley-like surface states in photonic superlattices}, journal = {Optics Letters}, volume = {34}, number = {11}, year = {2009}, month = {may}, pages = {1633}, publisher = {OSA}, abstract = {We provide what we believe to be the first experimental demonstration of linear Shockley-like surface states in an optically induced semi-infinite photonic superlattice. Such surface states appear only when the induced superlattice consisting of alternating strong and weak bonds is terminated properly at the surface. Our experimental results are in good agreement with our theoretical analysis.}, keywords = {2009, integrated optics, Nonlinear optics, Nonlinear optics at surfaces, Pulse propagation and temporal solitons, transverse effects in}, issn = {0146-9592}, url = {http://ol.osa.org/abstract.cfm?URI=ol-34-11-1633}, author = {Natalia Malkova and Hromada, Ivan and Wang, Xiaosheng and Garnett W Bryant and Chen, Zhigang} } @article { ISI:000267699500077, title = {Observation of percolation-induced two-dimensional metal-insulator transition in a Si MOSFET}, journal = {PHYSICAL REVIEW B}, volume = {79}, number = {23}, year = {2009}, month = {JUN}, issn = {1098-0121}, doi = {10.1103/PhysRevB.79.235307}, author = {Tracy, L. A. and Hwang, E. H. and Eng, K. and Ten Eyck, G. A. and Nordberg, E. P. and Childs, K. and Carroll, M. S. and Lilly, M. P. and S. Das Sarma} } @article {A.K.Thompson2008, title = {Observation of the He-3 (n,tp) reaction by detection of far-ultraviolet radiation}, journal = {Jour. Res. NIST}, number = {113}, year = {2008}, pages = {67{\textendash}78}, keywords = {2008, Single Fellow}, author = {A K Thompson and Charles W Clark and R E Vest and P P Hughes and M A Coplan and J W Cooper} } @article {Vaishnav2008, title = {Observing Zitterbewegung with Ultracold Atoms}, journal = {Phys. Rev. Lett.}, volume = {100}, number = {15}, year = {2008}, month = {apr}, keywords = {2008, Single Fellow}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v100/i15/e153002}, author = {J Vaishnav and Charles W Clark} } @article { ISI:000260574400086, title = {Orbital Landau level dependence of the fractional quantum Hall effect in quasi-two-dimensional electron layers: Finite-thickness effects}, journal = {PHYSICAL REVIEW B}, volume = {78}, number = {15}, year = {2008}, month = {OCT}, issn = {1098-0121}, doi = {10.1103/PhysRevB.78.155308}, author = {Peterson, Michael R. and Jolicoeur, Th. and S. Das Sarma} } @article {Ryu2007, title = {Observation of Persistent Flow of a Bose-Einstein Condensate in a Toroidal Trap}, journal = {Phys. Rev. Lett.}, volume = {99}, number = {26}, year = {2007}, month = {dec}, pages = {260401}, keywords = {2007, Multiple Fellows}, issn = {0031-9007}, url = {http://prl.aps.org/abstract/PRL/v99/i26/e260401}, author = {Changhyun Ryu and Andersen, M.F. and Pierre Clad{\'e} and Vasant Natarajan and Kristian Helmerson and William D Phillips} } @conference {Hester2007, title = {Optical trapping of nanoshells}, booktitle = {Proceedings of the SPIE}, volume = {6644}, number = {1}, year = {2007}, month = {sep}, pages = {66441B{\textendash}66441B{\textendash}9}, publisher = {SPIE}, organization = {SPIE}, keywords = {2007, Single Fellow}, issn = {0277786X}, url = {http://link.aip.org/link/?PSISDG/6644/66441B/1}, author = {Brooke C Hester and Alice M Crawford and Rani B Kishore and Kristian Helmerson and Halas, Naomi J and Levin, Carly} } @article {Naidon2006, title = {Optical Feshbach resonances of alkaline-earth-metal atoms in a one- or two-dimensional optical lattice}, journal = {Phys. Rev. A}, volume = {74}, number = {6}, year = {2006}, keywords = {2006, Single Fellow}, issn = {1050-2947}, url = {http://pra.aps.org/abstract/PRA/v74/i6/e062713}, author = {Pascal Naidon and Paul S Julienne} } @article {Reiner2006a, title = {Optically trapped aqueous droplets for single molecule studies}, journal = {Appl. Phys. Lett.}, volume = {89}, number = {1}, year = {2006}, pages = {013904}, publisher = {AIP}, keywords = {2006, Single Fellow}, issn = {00036951}, url = {http://www.mendeley.com/research/optically-trapped-aqueous-droplets-for-single-molecule-studies/}, author = {Joseph E Reiner and Alice M Crawford and Rani B Kishore and Goldner, Lori S. and Kristian Helmerson and Michael K Gilson} } @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} }