Pure Gravitational Back-Reaction Observables

TL;DR

This paper constructs a composite quantum gravitational observable suitable for homogeneous-isotropic conditions and proposes it as a measure of gravitational back-reaction during inflation.

Contribution

It introduces a new composite operator observable that addresses key issues in quantum gravity and extends it to quantify back-reaction in cosmological inflation.

Findings

Constructed a composite gravitational observable

Expanded the observable to first order in loop parameter

Proposed the observable as a physical measure of back-reaction

Abstract

After discussing the various issues regarding and requirements on pure quantum gravitational observables in homogeneous-isotropic conditions, we construct a composite operator observable satisfying most of them. We also expand it to first order in the loop counting parameter and suggest it as a physical quantifier of gravitational back-reaction in an initially inflating cosmology.