Modified cosmology through Barrow entropy

TL;DR

This paper explores how Barrow entropy modifies Friedmann equations and impacts cosmological evolution, including accelerated expansion and universe age, within a flat FRW universe framework.

Contribution

It introduces a modified cosmological model based on Barrow entropy, analyzing its effects on universe expansion and age, which differs from standard cosmology.

Findings

Model can explain current accelerated expansion.

Increasing Barrow parameter δ increases the scale factor.

Estimated universe age is smaller than in standard cosmology.

Abstract

We investigate the cosmological consequences of the modified Friedmann equations when the entropy associated with the apparent horizon, given by Barrow entropy, $S\sim A^{1+\delta/2}$, where $0\leq\delta\leq1$, represents the amount of the quantum-gravitational deformation of the horizon. We study implications of this model in a flat Friedmann-Robertson-Walker (FRW) universe with/without cosmological constant. Taking the cosmological constant into account, this model can describe the current accelerated expansion, although the transition from deceleration phase to the acceleration phase takes place in the lower redshifts. We investigate the evolution of the scale factor and show that with increasing $\delta$, the value of the scale factor increases as well. We also estimate the age of the universe in Barrow cosmology which is smaller than the age of the universe in standard cosmology.