De Sitter Breaking in Field Theory

TL;DR

The paper argues that maintaining manifest de Sitter invariance in gauge theories is impractical and often leads to inconsistencies, especially in quantum field theories where de Sitter invariant states do not exist.

Contribution

It challenges the usefulness and feasibility of de Sitter invariant gauges in field theory, highlighting issues with propagators and gauge invariance.

Findings

De Sitter invariant gauges complicate Green's functions and propagators.

De Sitter invariant states do not exist for interesting quantum fields.

Infrared divergences break de Sitter invariance even if invariant propagators existed.

Abstract

I argue against the widespread notion that manifest de Sitter invariance on the full de Sitter manifold is either useful or even attainable in gauge theories. Green's functions and propagators computed in a de Sitter invariant gauge are generally more complicated than in some noninvariant gauges. What is worse, solving the gauge-fixed field equations in a de Sitter invariant gauge generally leads to violations of the original, gauge invariant field equations. The most interesting free quantum field theories possess no normalizable, de Sitter invariant states. This precludes the existence of de Sitter invariant propagators. Even had such propagators existed, infrared divergent processes would still break de Sitter invariance.