Entropy production and correlation spreading in the interaction between particle detector and thermal baths

TL;DR

This paper investigates entropy production and correlation dynamics in a quantum system interacting with thermal baths using Gaussian quantum mechanics, revealing periodic behaviors and revivals that deepen understanding of thermodynamics in quantum regimes.

Contribution

It introduces a non-perturbative Gaussian quantum mechanics approach to analyze entropy and correlations in particle detector and thermal bath interactions, including both interacting and noninteracting baths.

Findings

Entropy production shows quantum recurrence and periodicity.

Correlation propagates periodically and causes revival of initial states.

Method can be extended to other models and may inform AdS/CFT studies.

Abstract

Entropy production is the key to the second law of thermodynamics, and it is well defined by considering a joint unitary evolution of a system $S$ and a thermal environment $E$. However, due to the diversity of the initial state and Hamiltonian of the system and environment, it is hard to evaluate the characterisation of entropy production. In the present work, we propose that the evolution of $S$ and $E$ can be solved non-perturbatively in the framework of Gaussian quantum mechanics (GQM). We study the entropy production and correlation spreading in the interaction between Unruh-DeWitt-like particle detector and thermal baths, where the particle detector is set to be a harmonic oscillator and the thermal baths are made of interacting and noninteracting Gaussian states. We can observe that the entropy production implies quantum recurrence and shows periodicity. In the case of interacting bath, the correlation propagates in a periodic system and leads to a revival of the initial state. Our analysis can be extended to any other models in the framework of GQM, and it may also shed some light on the AdS/CFT correspondence.