Interacting Quantum Field Theory in de Sitter Vacua

TL;DR

This paper clarifies the nature of quantum field theory in de Sitter space, emphasizing the importance of correlation function analyticity for defining vacua and developing perturbation theory.

Contribution

It demonstrates that the Mottola-Allen vacuum ambiguity is an artifact of free theory and establishes analyticity as a fundamental principle for interacting quantum fields in curved spacetime.

Findings

Mottola-Allen vacua are artifacts of free theory

Analyticity determines the vacuum uniquely in de Sitter space

Facilitates systematic perturbation theory development

Abstract

We discuss interacting quantum field theory in de Sitter space and argue that the Mottola-Allen vacuum ambiguity is an artifact of free field theory. The nature of the nonthermality of the MA-vacua is also clarified. We propose analyticity of correlation functions as a fundamental requirement of quantum field theory in curved spacetimes. In de Sitter space, this principle determines the vacuum unambiguously and facilitates the systematic development of perturbation theory.