A field theory characterization of interacting adiabatic particles in cosmology

TL;DR

This paper investigates the behavior of interacting adiabatic particles in cosmology, analyzing their quantum states and propagators, and examines dissipative effects on a two-level atom in an expanding universe.

Contribution

It introduces a field theory approach to characterize interacting adiabatic particles and their propagation in a cosmological setting, including dissipative effects.

Findings

Particle properties can be derived from two-point propagators.

Background expansion induces dissipative effects on particle propagation.

The approach links quantum state evolution to observable particle behavior.

Abstract

We explore the adiabatic particle excitations of an interacting field in a cosmological background. By following the time-evolution of the quantum state corresponding to the particle excitation, we show how the basic properties characterizing the particle propagation can be recovered from the two-point propagators. As an application, we study the background-induced dissipative effects on the propagation of a two-level atom in an expanding universe.