Local thermal observables in spatially open FRW spaces

TL;DR

This paper investigates local thermal observables in various spatially open FRW spacetimes, analyzing how different definitions of the Wick square affect local temperature measurements and their physical implications.

Contribution

It introduces a new approach to fixing the ambiguity in defining the Wick square in open FRW spaces and explores its physical consequences.

Findings

Different choices of Wick square influence local temperature measurements.

The approach clarifies thermal properties in Milne, open de Sitter, anti de Sitter, and Einstein static universes.

Physical implications vary between static and conformal vacua.

Abstract

Certain local thermal observables are considered in well-known examples of spatially open FRW spaces: Milne, open de Sitter and anti de Sitter as well as Einstein static universes. Another value for fixing the ambiguity in defining the Wick square and, hence, the local temperature is motivated in the last example. Physical consequences of that choice are discussed for static and conformal vacua in those spaces.