2019/05/31 by Bihui Zhu, Ana Maria Rey, Johannes Schachenmayer
Physics and Astronomy · #cond-mat.quant-gas #physics.comp-ph #quant-ph
paper · pdf · doi:10.1088/1367-2630/ab354d
published as New J. Phys. 21, 082001 (2019)
arxiv created 2019/08/15 · arxiv updated 2019/08/19
Numerical techniques to efficiently model out-of-equilibrium dynamics in interacting quantum many-body 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 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 correctly reproduces 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 closed system which feature quantum-thermalization at long times. By computing the Renyi entropy, currently an experimentally accessible quantifier of entanglement, 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.