@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:000462066300003,
title = {Bell{\textquoteright}s inequality, generalized concurrence and entanglement in qubits},
journal = {Int. J. Mod. Phys. A},
volume = {34},
number = {6-7},
year = {2019},
month = {MAR 10},
pages = {1950032},
publisher = {WORLD SCIENTIFIC PUBL CO PTE LTD},
type = {Article},
abstract = {It is well known that the maximal violation of the Bell{\textquoteright}s inequality for a two-qubit system is related to the entanglement formation in terms of a concurrence. However, a generalization of this relation to an n-qubit state has not been found. In this paper, we demonstrate some extensions of the relation between the upper bound of the Bell{\textquoteright}s violation and a generalized concurrence in several n-qubit states. In particular, we show the upper bound of the Bell{\textquoteright}s violation can be expressed as a function of the generalized concurrence, if a state can be expressed in terms of two variables. We apply the relation to the Wen-Plaquette model and show that the topological entanglement entropy can be extracted from the maximal Bell{\textquoteright}s violation.},
keywords = {Bell{\textquoteright}s inequality, entanglement, generalized concurrence, QUBIT},
issn = {0217-751X},
doi = {10.1142/S0217751X19500325},
author = {Chang, Po-Yao and Chu, Su-Kuan and Ma, Chen-Te}
}
@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: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:000492838300012,
title = {Two-dimensional dilaton gravity theory and lattice Schwarzian theory},
journal = {Int. J. Mod. Phys. A},
volume = {34},
number = {29},
year = {2019},
month = {OCT 20},
pages = {1950176},
publisher = {WORLD SCIENTIFIC PUBL CO PTE LTD},
type = {Article},
abstract = {We report a holographic study of a two-dimensional dilaton gravity theory with the Dirichlet boundary condition for the cases of nonvanishing and vanishing cosmological constants. Our result shows that the boundary theory of the two-dimensional dilaton gravity theory with the Dirichlet boundary condition for the case of nonvanishing cosmological constants is the Schwarzian term coupled to a dilaton field, while for the case of vanishing cosmological constant, a theory does not have a kinetic term. We also include the higher derivative term R-2, where R is the scalar curvature that is coupled to a dilaton field. We find that the form of the boundary theory is not modified perturbatively. Finally, we show that a lattice holographic picture is realized up to the second-order perturbation of boundary cutoff epsilon(2) under a constant boundary dilaton field and the nonvanishing cosmological constant by identifying the lattice spacing a of a lattice Schwarzian theory with the boundary cutoff epsilon of the two-dimensional dilaton gravity theory.},
keywords = {Dilaton gravity theory, higher derivative term, isometry, lattice Schwarzian theory},
issn = {0217-751X},
doi = {10.1142/S0217751X19501768},
author = {Chu, Su-Kuan and Ma, Chen-Te and Wu, Chih-Hung}
}
@article { ISI:000442061000013,
title = {Maximally entangled state and Bell{\textquoteright}s inequality in qubits},
journal = {ANNALS OF PHYSICS},
volume = {395},
year = {2018},
month = {AUG},
pages = {183-195},
keywords = {Bell{\textquoteright}s inequality, Maximally entangled state, Topological field theories, Topological states of matter},
issn = {0003-4916},
doi = {10.1016/j.aop.2018.05.016},
author = {Chu, Su-Kuan and Ma, Chen-Te and Miao, Rong-Xin and Wu, Chih-Hung}
}
@article { ISI:000411472400012,
title = {Bell{\textquoteright}s inequality and entanglement in qubits},
journal = {JOURNAL OF HIGH ENERGY PHYSICS},
number = {9},
year = {2017},
month = {SEP 20},
issn = {1029-8479},
doi = {10.1007/JHEP09(2017)100},
author = {Chang, Po-Yao and Chu, Su-Kuan and Ma, Chen-Te}
}