Semiclassical study of diagonal and offdiagonal functions in the eigenstate thermalization hypothesis

Fuente: arXiv
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Autores principales: Wang, Xiao, Wang, Wen-ge
Formato: Preprint
Publicado: 2022
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author Wang, Xiao
Wang, Wen-ge
author_facet Wang, Xiao
Wang, Wen-ge
contents The so-called eigenstate thermalization hypothesis (ETH), which has been tested in various manybody models by numerical simulations, supplies a way of understanding eventual thermalization and is believed to be important for understanding processes of thermalization. Two functions play important roles in the application of ETH, one for averaged diagonal elements and the other for the variance of offdiagonal elements of an observable addressed by ETH on the energy basis. For the former function, a semiclassical expression is known of the zeroth order of hbar, while, little is known analytically for the latter. In this paper, a semiclassical expression is derived for the former function, which includes higher-order contributions of hbar. And, a semiclassical approximation is derived for the latter function, under the assumption of negligible correlations among energy eigenfuntions on an action basis. Relevance of the analytical predictions are tested numerically in the Lipkin-Meshkov-Glick model.
format Preprint
id arxiv_https___arxiv_org_abs_2210_13183
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Semiclassical study of diagonal and offdiagonal functions in the eigenstate thermalization hypothesis
Wang, Xiao
Wang, Wen-ge
Statistical Mechanics
Chaotic Dynamics
Quantum Physics
The so-called eigenstate thermalization hypothesis (ETH), which has been tested in various manybody models by numerical simulations, supplies a way of understanding eventual thermalization and is believed to be important for understanding processes of thermalization. Two functions play important roles in the application of ETH, one for averaged diagonal elements and the other for the variance of offdiagonal elements of an observable addressed by ETH on the energy basis. For the former function, a semiclassical expression is known of the zeroth order of hbar, while, little is known analytically for the latter. In this paper, a semiclassical expression is derived for the former function, which includes higher-order contributions of hbar. And, a semiclassical approximation is derived for the latter function, under the assumption of negligible correlations among energy eigenfuntions on an action basis. Relevance of the analytical predictions are tested numerically in the Lipkin-Meshkov-Glick model.
title Semiclassical study of diagonal and offdiagonal functions in the eigenstate thermalization hypothesis
topic Statistical Mechanics
Chaotic Dynamics
Quantum Physics
url https://arxiv.org/abs/2210.13183