Inflationary Consistency Conditions from a Wavefunctional Perspective

TL;DR

This paper demonstrates that the squeezed limit of inflationary expectation values is a consequence of wavefunction reparametrization invariance, implying local non-Gaussianity in single field inflation is a gauge artifact with no physical effect.

Contribution

It introduces a wavefunctional approach to derive inflationary consistency conditions, showing that local non-Gaussianity is a gauge artifact in single field inflation.

Findings

Squeezed limit expectation values follow from wavefunction invariance.

Local non-Gaussianity in single field inflation is a gauge artifact.

Formalism applies broadly to theories with diffeomorphism invariance.

Abstract

It is shown that the squeezed limit of inflationary expectation values follows from reparametrization invariance of the wavefunction of the universe. This translates into a constraint on the longitudinal modes of functional derivatives of the wavefunction. Thus, the local non-Gaussianity induced by single field inflation is purely a gauge artifact, and should not yield a physically measurable effect. We focus on Einstein gravity in de Sitter space and single field inflation, although the formalism only relies on the diffeomorphism invariance of the theory, and thus applies to any theory of gravity.