Classicality, Markovianity and local detailed balance from pure state dynamics

Fuente: arXiv
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Main Authors: Strasberg, Philipp, Winter, Andreas, Gemmer, Jochen, Wang, Jiaozi
Format: Preprint
Published: 2022
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author Strasberg, Philipp
Winter, Andreas
Gemmer, Jochen
Wang, Jiaozi
author_facet Strasberg, Philipp
Winter, Andreas
Gemmer, Jochen
Wang, Jiaozi
contents When describing the effective dynamics of an observable in a many-body system, the repeated randomness assumption, which states that the system returns in a short time to a maximum entropy state, is a crucial hypothesis to guarantee that the effective dynamics is classical, Markovian and obeys local detailed balance. While the latter behaviour is frequently observed in naturally occurring processes, the repeated randomness assumption is in blatant contradiction to the microscopic reversibility of the system. Here, we show that the use of the repeated randomness assumption can be justified in the description of the effective dynamics of an observable that is both slow and coarse, two properties we will define rigorously. Then, our derivation will invoke essentially only the eigenstate thermalization hypothesis and typicality arguments. While the assumption of a slow observable is subtle, as it provides only a necessary but not sufficient condition, it also offers a unifying perspective applicable to, e.g., open systems as well as collective observables of many-body systems. All our ideas are numerically verified by studying density waves in spin chains.
format Preprint
id arxiv_https___arxiv_org_abs_2209_07977
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Classicality, Markovianity and local detailed balance from pure state dynamics
Strasberg, Philipp
Winter, Andreas
Gemmer, Jochen
Wang, Jiaozi
Quantum Physics
Statistical Mechanics
When describing the effective dynamics of an observable in a many-body system, the repeated randomness assumption, which states that the system returns in a short time to a maximum entropy state, is a crucial hypothesis to guarantee that the effective dynamics is classical, Markovian and obeys local detailed balance. While the latter behaviour is frequently observed in naturally occurring processes, the repeated randomness assumption is in blatant contradiction to the microscopic reversibility of the system. Here, we show that the use of the repeated randomness assumption can be justified in the description of the effective dynamics of an observable that is both slow and coarse, two properties we will define rigorously. Then, our derivation will invoke essentially only the eigenstate thermalization hypothesis and typicality arguments. While the assumption of a slow observable is subtle, as it provides only a necessary but not sufficient condition, it also offers a unifying perspective applicable to, e.g., open systems as well as collective observables of many-body systems. All our ideas are numerically verified by studying density waves in spin chains.
title Classicality, Markovianity and local detailed balance from pure state dynamics
topic Quantum Physics
Statistical Mechanics
url https://arxiv.org/abs/2209.07977