Isotropization of locally rotationally symmetric Bianchi-I universe in $f(Q)$-gravity

TL;DR

This paper investigates how an anisotropic Bianchi-I universe in $f(Q)$ gravity evolves towards isotropy, showing that inflation can diminish initial anisotropies even with anisotropic fluids present.

Contribution

It introduces a model of early universe evolution in $f(Q)$ gravity with anisotropic spacetime and demonstrates isotropization due to inflation within this framework.

Findings

Universe starts with anisotropic geometry and fluid.

Inflation causes anisotropies to fade over time.

Models support isotropization despite anisotropic fluids.

Abstract

Despite having the somewhat successful description of accelerated cosmology, the early evolution of the universe always challenges mankind. Our promising approach lies in a new class of symmetric teleparallel theory of gravity named $f(Q)$, where the non-metricity scalar $Q$ is responsible for the gravitational interaction, which may resolve some of the issues. To study the early evolution of the universe, we presume an anisotropic locally rotationally symmetric (LRS) Bianchi-I spacetime and derive the motion equations. We discuss the profiles of energy density, equation of state and skewness parameter and observe that our models archive anisotropic spatial geometry in the early phase of the universe with a possible presence of anisotropic fluid and as time goes on, even in the presence of an anisotropic fluid, the universe could approach isotropy due to inflation and the anisotropy of the fluid fades away at the same time.