Semiclassical quench dynamics of Bose gases in optical lattices

Nagao, Kazuma; Kunimi, Masaya; Takasu, Yoshio; Takahashi, Yoshiro; Danshita, Ippei

doi:10.1103/physreva.99.023622

Cited by 24 publications

(42 citation statements)

References 79 publications

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“…This method is not suited for computing the nonlocal spatial correlations analyzed in the present work because it ignores the momentum dependence of the correlation functions. Instead, we choose the TWA approximation, which is supposed to accurately capture semiclassical dynamics of the BHM at least on a short time scale [see (29) and references therein]. In Fig.…”

Section: Discussion and Outlookmentioning

confidence: 99%

“…We use the exact MPS method in the 1D case, finding excellent agreement with the observations. As for the case of the quench toward a deep superfluid region in 3D, the time evolution of the kinetic and interaction energies is directly compared with numerical results obtained using the truncated Wigner approximation (TWA) on the basis of the Gross-Pitaevskii mean-field theory (29). The good agreement between the experiment and the theory establishes the predictive power of the TWA for this type of quench.…”

Section: Introductionmentioning

confidence: 94%

“…A two-point spatial correlation as a function of the distance of the two points has been the intense theoretical interest (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30), and in fact, in 1D systems, it has been shown that access to such a correlation function allows for exploring the dynamical spreading of quantum information, which is of great interest in connection with the Lieb-Robinson (LR) bound (11,31). An exact computation of the spatiotemporal evolution of these two-point correlations is, however, generally intractable for a long time scale or in higher dimensions.…”

Section: Introductionmentioning

confidence: 99%

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Energy redistribution and spatiotemporal evolution of correlations after a sudden quench of the Bose-Hubbard model

et al. 2020

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An optical lattice quantum simulator is an ideal experimental platform to investigate nonequilibrium dynamics of a quantum many-body system, which is, in general, hard to simulate with classical computers. Here, we use our quantum simulator of the Bose-Hubbard model to study dynamics far from equilibrium after a quantum quench. We successfully confirm the energy conservation law in the one- and three-dimensional systems and extract the propagation velocity of the single-particle correlation in the one- and two-dimensional systems. We corroborate the validity of our quantum simulator through quantitative comparisons between the experiments and the exact numerical calculations in one dimension. In the computationally hard cases of two or three dimensions, by using the quantum-simulation results as references, we examine the performance of a numerical method, namely, the truncated Wigner approximation, revealing its usefulness and limitation. This work constitutes an exemplary case for the usage of analog quantum simulators.

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Section: Discussion and Outlookmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

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Energy redistribution and spatiotemporal evolution of correlations after a sudden quench of the Bose-Hubbard model

et al. 2020

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“…This implies that in models which thermalize, e.g.which are not many-body localized because of disorder, the method can give accurate predictions over all time-scales. The method can be applied to any model consisting of discrete coupled Hilbert spaces, such as spin systems featuring  ( ) SU super-exchange interactions [73], the so called Subir-Ye-Kitaev models [74][75][76], Bose-Hubbard models [77], etc.…”

Section: Discussionmentioning

confidence: 99%

A generalized phase space approach for solving quantum spin dynamics

2019

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Numerical techniques to efficiently model out-of-equilibrium dynamics in interacting quantum manybody systems are key for advancing our capability to harness and understand complex quantum matter.Here we propose a new numerical approach which we refer to as generalized discrete truncated Wigner approximation (GDTWA). It is based on a discrete semi-classical phase space sampling and allows to investigate quantum dynamics in lattice spin systems with arbitrary S1/2. We show that the GDTWA can accurately simulate dynamics of large ensembles in arbitrary dimensions. We apply it for S>1/2 spin-models with dipolar long-range interactions, a scenario arising in recent experiments with magnetic atoms. We show that the method can capture beyond mean-field effects, not only at short times, but it also can correctly reproduce long time quantum-thermalization dynamics. We benchmark the method with exact diagonalization in small systems, with perturbation theory for short times, and with analytical predictions made for models which feature quantum-thermalization at long times. We apply our method to study dynamics in large S>1/2 spin-models and compute experimentally accessible observables such as Zeeman level populations, contrast of spin coherence, spin squeezing, and entanglement quantified by single-spin Renyi entropies. We reveal that large S systems can feature larger entanglement than corresponding S=1/2 systems. Our analyses demonstrate that the GDTWA can be a powerful tool for modeling complex spin dynamics in regimes where other state-of-the art numerical methods fail. case also the mean-field equations are not necessarily closed unless also intra-spin correlations are assumed to factorize. Those cases are not accounted for in the approach described here, but we will properly include them in our GDTWA method below.

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“…The cold atoms in optical lattice offer precise control over many system parameters and the high resolution image technique allows probing their correlation dynamics [1,2]. Over the last few years, the forefront research in this direction characterizes many-body systems mainly with contact interaction [3][4][5][6][7][8][9][10][11]. The onset of thermalization caused by the interparticle interaction has been widely discussed in many contexts [4,[12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Correlation Dynamics of Dipolar Bosons in 1D Triple Well Optical Lattice

2019

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The concept of spontaneous symmetry breaking and off-diagonal long-range order (ODLRO) are associated with Bose–Einstein condensation. However, as in the system of reduced dimension the effect of quantum fluctuation is dominating, the concept of ODLRO becomes more interesting, especially for the long-range interaction. In the present manuscript, we study the correlation dynamics triggered by lattice depth quench in a system of three dipolar bosons in a 1D triple-well optical lattice from the first principle using the multiconfigurational time-dependent Hartree method for bosons (MCTDHB). Our main motivation is to explore how ODLRO develops and decays with time when the system is brought out-of-equilibrium by a sudden change in the lattice depth. We compare results of dipolar bosons with contact interaction. For forward quench ( V f > V i ) , the system exhibits the collapse–revival dynamics in the time evolution of normalized first- and second-order Glauber’s correlation function, time evolution of Shannon information entropy both for the contact as well as for the dipolar interaction which is reminiscent of the one observed in Greiner’s experiment [Nature, 415 (2002)]. We define the collapse and revival time ratio as the figure of merit ( τ ) which can uniquely distinguish the timescale of dynamics for dipolar interaction from that of contact interaction. In the reverse quench process ( V i > V f ) , for dipolar interaction, the dynamics is complex and the system does not exhibit any definite time scale of evolution, whereas the system with contact interaction exhibits collapse–revival dynamics with a definite time-scale. The long-range repulsive tail in the dipolar interaction inhibits the spreading of correlation across the lattice sites.

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Semiclassical quench dynamics of Bose gases in optical lattices

Cited by 24 publications

References 79 publications

Energy redistribution and spatiotemporal evolution of correlations after a sudden quench of the Bose-Hubbard model

Energy redistribution and spatiotemporal evolution of correlations after a sudden quench of the Bose-Hubbard model

A generalized phase space approach for solving quantum spin dynamics

Correlation Dynamics of Dipolar Bosons in 1D Triple Well Optical Lattice

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