Trajectory-Resolved Weiss Fields for Quantum Spin Dynamics

Fuente: arXiv
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Auteurs principaux: Begg, S. E., Green, A. G., Bhaseen, M. J.
Format: Preprint
Publié: 2022
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author Begg, S. E.
Green, A. G.
Bhaseen, M. J.
author_facet Begg, S. E.
Green, A. G.
Bhaseen, M. J.
contents We explore the dynamics of quantum spin systems in two and three dimensions using an exact mapping to classical stochastic processes. In recent work we explored the effectiveness of sampling around the mean field evolution as determined by a stochastically averaged Weiss field. Here, we show that this approach can be significantly extended by sampling around the instantaneous Weiss field associated with each stochastic trajectory taken separately. This trajectory-resolved approach incorporates sample to sample fluctuations and allows for longer simulation times. We demonstrate the utility of this approach for quenches in the two-dimensional and three-dimensional quantum Ising model. We show that the method is particularly advantageous in situations where the average Weiss-field vanishes, but the trajectory-resolved Weiss fields are non-zero. We discuss the connection to the gauge-P phase space approach, where the trajectory-resolved Weiss field can be interpreted as a gauge degree of freedom.
format Preprint
id arxiv_https___arxiv_org_abs_2209_09409
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Trajectory-Resolved Weiss Fields for Quantum Spin Dynamics
Begg, S. E.
Green, A. G.
Bhaseen, M. J.
Strongly Correlated Electrons
Quantum Physics
We explore the dynamics of quantum spin systems in two and three dimensions using an exact mapping to classical stochastic processes. In recent work we explored the effectiveness of sampling around the mean field evolution as determined by a stochastically averaged Weiss field. Here, we show that this approach can be significantly extended by sampling around the instantaneous Weiss field associated with each stochastic trajectory taken separately. This trajectory-resolved approach incorporates sample to sample fluctuations and allows for longer simulation times. We demonstrate the utility of this approach for quenches in the two-dimensional and three-dimensional quantum Ising model. We show that the method is particularly advantageous in situations where the average Weiss-field vanishes, but the trajectory-resolved Weiss fields are non-zero. We discuss the connection to the gauge-P phase space approach, where the trajectory-resolved Weiss field can be interpreted as a gauge degree of freedom.
title Trajectory-Resolved Weiss Fields for Quantum Spin Dynamics
topic Strongly Correlated Electrons
Quantum Physics
url https://arxiv.org/abs/2209.09409