A Measure of Cosmological Acceleration

TL;DR

This paper introduces an invariant measure of local acceleration to quantify quantum gravitational back-reaction during inflation, applicable even without a scalar inflaton, and evaluates it using stochastic methods in pure quantum gravity.

Contribution

It proposes a new invariant measure of local acceleration for assessing quantum back-reaction in inflation, independent of scalar fields, and applies stochastic techniques for evaluation.

Findings

Derived a one-loop order expression for local acceleration in Lambda-driven inflation.

Demonstrated the measure's suitability for models lacking a scalar inflaton.

Provided a framework for analyzing quantum gravitational effects during inflation.

Abstract

We propose quantifying the quantum gravitational back-reaction on inflation with an invariant measure of the local acceleration rather than the expansion rate. Our observable is suitable for models in which there is no scalar inflaton to provide a preferred velocity field with which to define the expansion. As an example, we use stochastic techniques to evaluate the local acceleration at one loop order for Lambda-driven inflation in pure quantum gravity.