Anisotropic Universe in $f(Q,T)$ gravity, a novel study

TL;DR

This paper explores anisotropic cosmological models within the $f(Q,T)$ gravity framework, deriving equations for LRS Bianchi-I spacetime and constraining model parameters using observational data.

Contribution

It extends $f(Q,T)$ gravity to anisotropic universes and employs MCMC methods to constrain model parameters with observational datasets.

Findings

Derived motion equations for anisotropic $f(Q,T)$ gravity.

Constrained model parameters using Hubble and SNe Ia data.

Analyzed the impact of anisotropy on cosmological evolution.

Abstract

$f(Q,T)$ theory of gravity is very recently proposed to incorporate within the action Lagrangian, the trace $T$ of the energy-momentum tensor along with the non-metricity scalar $Q$. The cosmological application of this theory in a spatially flat isotropic and homogeneous Universe is well-studied. However, our Universe is not isotropic since the Planck era and therefore to study a complete evolution of the Universe we must investigate the $f(Q,T)$ theory in a model with a small anisotropy. This motivated us to presume a locally rotationally symmetric (LRS) Bianchi-I spacetime and derive the motion equations. We analyse the model candidate $f(Q,T)=\alpha Q^{n+1}+\beta T$, and to constrain the parameter $n$, we employ the statistical Markov chain Monte Carlo (MCMC) method with the Bayesian approach using two independent observational datasets, namely, the Hubble datasets, and Type Ia supernovae (SNe Ia) datasets.