Gaussian ancillary bombardment

TL;DR

This paper provides a detailed analysis of how Gaussian quantum systems evolve under rapid bombardment by Gaussian ancillae, revealing conditions for thermalization and challenging assumptions about its robustness.

Contribution

It introduces a comprehensive analysis of Gaussian ancillary bombardment and identifies specific conditions under which thermalization occurs in such systems.

Findings

Only certain system-environment couplings lead to thermalization.

Thermalization is less robust under Markovian microinteraction assumptions.

The analysis applies to harmonic oscillators coupled to thermal reservoirs.

Abstract

We analyze in full detail the time evolution of an open Gaussian quantum system rapidly bombarded by Gaussian ancillae. As a particular case this analysis covers the thermalization (or not) of a harmonic oscillator coupled to a thermal reservoir made of harmonic oscillators. We derive general results for this scenario and apply them to the problem of thermalization. We show that only a particular family of system-environment couplings will cause the system to thermalize to the temperature of its environment. We discuss that if we want to understand thermalization as ensuing from the Markovian interaction of a system with the individual microconstituents of its (thermal) environment then the process of thermalization is not as robust as one might expect.