Eur. Phys. J. Plus (2022) 137: 821
https://doi.org/10.1140/epjp/s13360-022-03053-3

Regular Article

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

¹ Center for Gravitation and Cosmology, College of Physical Science and Technology, Yangzhou University, 180 Siwangting Road, 225002, Yangzhou City, Jiangsu Province, China
² Shanghai Frontier Science Center for Gravitational Wave Detection, Shanghai Jiao Tong University, 200240, Shanghai, China

^a haoxu@yzu.edu.cn

Received: 29 March 2022
Accepted: 8 July 2022
Published online: 16 July 2022

Abstract

Entropy production is the key behind 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 initial state and Hamiltonian of the system and environment, it is hard to evaluate the characterization 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 non-interacting 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.