A covariant and gauge invariant formulation of the cosmological "backreaction"

TL;DR

This paper presents a gauge-invariant, covariant framework for understanding how inhomogeneities influence the average evolution of the universe, addressing the cosmological backreaction problem.

Contribution

It introduces a novel covariant and gauge-invariant averaging method to analyze the impact of inhomogeneities on cosmic evolution.

Findings

Provides explicit gauge-invariant equations for backreaction effects

Enables analysis of classical and quantum inhomogeneities

Offers a consistent covariant approach to cosmological averaging

Abstract

Using our recent proposal for defining gauge invariant averages we give a general-covariant formulation of the so-called cosmological "backreaction". Our effective covariant equations allow us to describe in explicitly gauge invariant form the way classical or quantum inhomogeneities affect the average evolution of our Universe.