A graviton propagator for inflation

TL;DR

This paper develops scalar and graviton propagators in quasi de Sitter space, incorporating slow roll corrections, enabling detailed analysis of quantum effects during inflation.

Contribution

It introduces a method to construct propagators in quasi de Sitter space with first-order slow roll corrections, extending previous de Sitter models.

Findings

Propagators include epsilon correction to effective mass.

Limit epsilon→0 recovers de Sitter vacuum with broken symmetry.

Enables self-consistent study of quantum back-reaction during inflation.

Abstract

We construct the scalar and graviton propagator in quasi de Sitter space up to first order in the slow roll parameter $\epsilon\equiv -\dot{H}/H^2$. After a rescaling, the propagators are similar to those in de Sitter space with an $\epsilon$ correction to the effective mass. The limit $\epsilon\to 0$ corresponds to the E(3) vacuum that breaks de Sitter symmetry, but does not break spatial isotropy and homogeneity. The new propagators allow for a self-consistent, dynamical study of quantum back-reaction effects during inflation.