Timescales of quantum and classical chaotic spin models evolving toward equilibrium

Fuente: arXiv
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Main Authors: Borgonovi, Fausto, Izrailev, Felix M., Santos, Lea F.
Format: Preprint
Published: 2023
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author Borgonovi, Fausto
Izrailev, Felix M.
Santos, Lea F.
author_facet Borgonovi, Fausto
Izrailev, Felix M.
Santos, Lea F.
contents We investigate quench dynamics in a one-dimensional spin model, comparing both quantum and classical descriptions. Our primary focus is on the different timescales involved in the evolution of the observables as they approach statistical relaxation. Numerical simulations, supported by semi-analytical analysis, reveal that the relaxation of single-particle energies (global quantity) and on-site magnetization (local observable) occurs on a timescale independent of the system size $L$. This relaxation process is equally well-described by classical equations of motion and quantum solutions, demonstrating excellent quantum-classical correspondence, provided the system be strongly chaotic. The correspondence persists even for small quantum spin values ($S=1$), where a semi-classical approximation is not applicable. Conversely, for the participation ratio, which characterizes the initial state spread in the many-body Hilbert space and which lacks a classical analogue, the relaxation timescale is system-size dependent.
format Preprint
id arxiv_https___arxiv_org_abs_2307_05681
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Timescales of quantum and classical chaotic spin models evolving toward equilibrium
Borgonovi, Fausto
Izrailev, Felix M.
Santos, Lea F.
Statistical Mechanics
Quantum Physics
We investigate quench dynamics in a one-dimensional spin model, comparing both quantum and classical descriptions. Our primary focus is on the different timescales involved in the evolution of the observables as they approach statistical relaxation. Numerical simulations, supported by semi-analytical analysis, reveal that the relaxation of single-particle energies (global quantity) and on-site magnetization (local observable) occurs on a timescale independent of the system size $L$. This relaxation process is equally well-described by classical equations of motion and quantum solutions, demonstrating excellent quantum-classical correspondence, provided the system be strongly chaotic. The correspondence persists even for small quantum spin values ($S=1$), where a semi-classical approximation is not applicable. Conversely, for the participation ratio, which characterizes the initial state spread in the many-body Hilbert space and which lacks a classical analogue, the relaxation timescale is system-size dependent.
title Timescales of quantum and classical chaotic spin models evolving toward equilibrium
topic Statistical Mechanics
Quantum Physics
url https://arxiv.org/abs/2307.05681