Behavior of a bipartite system in a cavity

TL;DR

This paper investigates how a bipartite atomic system behaves in different cavity sizes, revealing dissipation in large cavities and persistent oscillations in small ones, with entropy remaining constant over time.

Contribution

It provides a detailed analysis of the time evolution of dressed atomic states in cavities of varying sizes, highlighting the distinct dynamical behaviors and entropy invariance.

Findings

Large cavities lead to system dissipation.

Small cavities cause persistent oscillations.

Von Neumann entropy remains constant regardless of cavity size.

Abstract

We study the time evolution of a superposition of product states of two dressed atoms in a spherical cavity in the situations of an arbitrarily large cavity (free space) and of a small one. In the large-cavity case, the system dissipates, whereas, for the small cavity, the system evolves in an oscillating way and never completely decays. We verify that the von Neumann entropy for such a system does not depend on time, nor on the size of the cavity