Anisotropic Universe in f(Q) gravity with Hybrid expansion

TL;DR

This paper explores anisotropic cosmological models within the f(Q) gravity framework, using hybrid expansion law to analyze early universe evolution, anisotropy, and transition to dark energy, revealing potential isotropization over time.

Contribution

It introduces solutions for Bianchi type-I models in f(Q) gravity with hybrid expansion, highlighting anisotropy evolution and late-time acceleration.

Findings

Universe starts with anisotropic geometry and phantom-like behavior.

Models suggest a transition from anisotropy to isotropy over time.

Universe approaches dark energy dominance at present epoch.

Abstract

Despite having a reasonably successful account of accelerated cosmology, understanding the early evolution of Universe has always been difficult for mankind. Our promising strategy is based on a novel class of symmetric teleparallel theories of gravity called $f(Q)$, in which the gravitational interaction is caused by the non-metricity scalar $Q$, which may help to solve some problems. We consider the locally rotationally symmetric (LRS) Bianchi type-I spacetime cosmological models and derive the motion of equations to study the early evolution of the cosmos. By assuming the Hybrid Expansion Law (HEL) for the average scale factor, we are able to determine the solutions to the field equations of Bianchi type-I spacetime. We discuss the energy density profile, the equation of state, and the skewness parameter and conclude that our models preserve anisotropic spatial geometry during the early stages of the Universe with the possibility of an anisotropic fluid present. However, as time goes on, even in the presence of an anisotropic fluid, the Universe may move towards isotropy due to inflation while the anisotropy of the fluid dims away at the same time. It is seen from the squared speed of sound that Universe shows phantom nature at the beginning then approaches to dark energy at present epoch. We analyze both geometrical and physical behaviors of the derived model.