A note on Quantum Fields in Conformally flat Space-times

TL;DR

This paper introduces a technique to relate scalar fields with different masses across conformally flat space-times, enabling analysis of energy conditions and correlators in cosmological models like FRW space-times.

Contribution

The paper presents a novel method to connect scalar fields in different conformally flat backgrounds, facilitating the study of their physical properties and constraints.

Findings

Energy conditions impose constraints on related space-times.

The technique allows computation of correlators in different backgrounds.

Applications to FRW space-times demonstrate the method's utility.

Abstract

We develop a technique relating scalar fields with different masses in different conformally flat space-times. We apply this technique to the case of FRW space-times, with $k=\pm 1,0$, and discuss several examples. We also study various energy conditions and discuss how they constrain the space-times related by this technique. In addition, we use this technique to study correlators for the related space-times in an example.