The taming of the alpha-vacuum

TL;DR

This paper discusses how the propagator in de Sitter space's alpha-vacua must be modified with antipodal sources to ensure renormalizability when the state breaks certain symmetries.

Contribution

It introduces a method to adapt the propagator for alpha-vacua in de Sitter space to maintain renormalizability by incorporating antipodal sources.

Findings

Propagator for alpha-vacua requires antipodal sources.

Ensures renormalizability in symmetry-breaking states.

Provides a consistent framework for quantum fields in de Sitter space.

Abstract

When examining a field theory in a general state, the propagator must be made consistent with that state and new counterterms are allowed if the state breaks some of the space-time's symmetries. This talk describes the specific example of how the propagator for the alpha-vacua of de Sitter space must become the Green's function for two antipodal sources to obtain a renormalizable theory.