Thermal equilibration between two quantum systems

TL;DR

This paper demonstrates how two isolated quantum systems initially at different temperatures relax to a common Gibbs-like equilibrium state through a chain of intermediate states, with conditions verified by two models.

Contribution

It identifies specific conditions for thermal equilibration between quantum systems and confirms the process through two distinct models.

Findings

Quantum systems relax to Gibbs-like states

Thermalization occurs via intermediate Gibbs-like states

Conditions for equilibration are explicitly specified

Abstract

Two identical finite quantum systems prepared initially at different temperatures, isolated from the environment, and subsequently brought into contact are demonstrated to relax towards Gibbs-like quasi-equilibrium states with a common temperature and small fluctuations around the time-averaged expectation values of generic observables. The temporal thermalization process proceeds via a chain of intermediate Gibbs-like states. We specify the conditions under which this scenario occurs and corroborate the quantum equilibration with two different models.