Correlations of Quantum Fields on Robertson-Walker Spacetimes

TL;DR

This paper derives formulas for quantum field correlations on Robertson-Walker spacetimes, revealing potential influences on early universe structure formation using algebraic and constructive quantum field theory methods.

Contribution

It provides the first explicit formulas for quantum field correlations in Robertson-Walker spacetimes, extending understanding beyond Minkowski spacetime.

Findings

Correlations depend on spacetime geometry

Disjoint past horizons do not necessarily imply absence of correlations

Formulas could impact models of early universe structure formation

Abstract

It is a well known fact that quantum fields on Minkowski spacetime are correlated for each pair of spacetime regions. In Robertson-Walker spacetimes there are spacelike separated regions with disjoint past horizons but the absence of correlations in that case was never proved. We derive in this paper formulae for correlations of quantum fields on Robertson-Walker spacetimes. Such correlations could have reasonably influenced the formation of structure in the early universe. We use methods of algebraic and constructive quantum field theory.