Quantum Thermalization via Travelling Waves

Fuente: arXiv
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Main Authors: Picano, Antonio, Biroli, Giulio, Schirò, Marco
Format: Preprint
Published: 2024
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author Picano, Antonio
Biroli, Giulio
Schirò, Marco
author_facet Picano, Antonio
Biroli, Giulio
Schirò, Marco
contents Isolated quantum many-body systems which thermalize under their own dynamics are expected to act as their own thermal baths, thereby bringing their local subsystems to thermal equilibrium. Here we show that the infinite-dimensional limit of a quantum lattice model, as described by Dynamical Mean-Field theory (DMFT), provides a natural framework to understand this self-consistent thermalization process. Using the Fermi-Hubbard model as working example, we demonstrate that the emergence of a self-consistent bath thermalising the system is characterized by a sharp thermalization front, moving balistically and separating the initial condition from the long-time thermal fixed point. We characterize the full DMFT dynamics through an effective temperature for which we derive a travelling-wave equation of the Fisher-Kolmogorov-Petrovsky-Piskunov (FKPP) type. This equation allows to predict the asymptotic shape of the front and its velocity, which match perfectly the full DMFT numerics. Our results provide a new angle to understand the onset of quantum thermalisation in closed isolated systems.
format Preprint
id arxiv_https___arxiv_org_abs_2405_19884
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Quantum Thermalization via Travelling Waves
Picano, Antonio
Biroli, Giulio
Schirò, Marco
Strongly Correlated Electrons
Isolated quantum many-body systems which thermalize under their own dynamics are expected to act as their own thermal baths, thereby bringing their local subsystems to thermal equilibrium. Here we show that the infinite-dimensional limit of a quantum lattice model, as described by Dynamical Mean-Field theory (DMFT), provides a natural framework to understand this self-consistent thermalization process. Using the Fermi-Hubbard model as working example, we demonstrate that the emergence of a self-consistent bath thermalising the system is characterized by a sharp thermalization front, moving balistically and separating the initial condition from the long-time thermal fixed point. We characterize the full DMFT dynamics through an effective temperature for which we derive a travelling-wave equation of the Fisher-Kolmogorov-Petrovsky-Piskunov (FKPP) type. This equation allows to predict the asymptotic shape of the front and its velocity, which match perfectly the full DMFT numerics. Our results provide a new angle to understand the onset of quantum thermalisation in closed isolated systems.
title Quantum Thermalization via Travelling Waves
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2405.19884