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Autori principali: Khan, Sakil, Rathore, Lokendra Singh, Jain, Sachin
Natura: Preprint
Pubblicazione: 2024
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Accesso online:https://arxiv.org/abs/2401.16488
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author Khan, Sakil
Rathore, Lokendra Singh
Jain, Sachin
author_facet Khan, Sakil
Rathore, Lokendra Singh
Jain, Sachin
contents Thermalization of a system when interacting with a thermal bath is an interesting problem. If a system eventually reaches a thermal state in the long time limit, it's expected that its density matrix would resemble the mean-force Gibbs state. Moreover, the correlation function must satisfy the Kubo-Martin-Schwinger (KMS) condition or equivalently the Fluctuation-Dissipation Relation (FDR). In this paper, we derive a formal expression for the non-Markovian two-point function within the context of the weak coupling limit. Using this expression, we explicitly compute the two-point function for specific models, demonstrating their adherence to the KMS. In addition, we have formulated a non-perturbative approach in the form of a self-consistent approximation that includes a partial resummation of perturbation theory. This approach can capture strong coupling phenomena while still relying on simple equations. Notably, we verify that the two-point function obtained through this method also satisfies the KMS condition.
format Preprint
id arxiv_https___arxiv_org_abs_2401_16488
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Steady state correlation function beyond the standard weak coupling limit and consistency with KMS relation
Khan, Sakil
Rathore, Lokendra Singh
Jain, Sachin
Quantum Physics
Statistical Mechanics
High Energy Physics - Theory
Thermalization of a system when interacting with a thermal bath is an interesting problem. If a system eventually reaches a thermal state in the long time limit, it's expected that its density matrix would resemble the mean-force Gibbs state. Moreover, the correlation function must satisfy the Kubo-Martin-Schwinger (KMS) condition or equivalently the Fluctuation-Dissipation Relation (FDR). In this paper, we derive a formal expression for the non-Markovian two-point function within the context of the weak coupling limit. Using this expression, we explicitly compute the two-point function for specific models, demonstrating their adherence to the KMS. In addition, we have formulated a non-perturbative approach in the form of a self-consistent approximation that includes a partial resummation of perturbation theory. This approach can capture strong coupling phenomena while still relying on simple equations. Notably, we verify that the two-point function obtained through this method also satisfies the KMS condition.
title Steady state correlation function beyond the standard weak coupling limit and consistency with KMS relation
topic Quantum Physics
Statistical Mechanics
High Energy Physics - Theory
url https://arxiv.org/abs/2401.16488