Study of cosmic backreaction on the future evolution of an accelerating universe using multiple domains

TL;DR

This paper examines how inhomogeneities in the universe influence its future acceleration, showing that backreaction can slow down or reverse acceleration, affecting cosmic evolution predictions.

Contribution

It introduces a multi-domain approach within the Buchert framework to analyze the impact of inhomogeneities on the universe's future dynamics.

Findings

Backreaction can slow down future acceleration.

Inhomogeneities may lead to a future decelerating epoch.

Different partitioning methods yield consistent qualitative results.

Abstract

We investigate the effect of backreaction due to inhomogeneities on the evolution of the present Universe by considering the Universe to be partitioned into multiple domains within the Buchert framework. Taking the observed present acceleration of the universe as an essential input, we study the effect of inhomogeneities on the future evolution. We find that the backreaction from inhomogeneities causes the acceleration to slow down in the future for a range of initial configurations and model parameters, and even lead in certain cases to the emergence of a future decelerating epoch. We consider two different partitioning of the Universe and perform a comparative analysis for the two cases on the behaviour of the acceleration and backreaction of the Universe.