Thermodynamic implications and observational constraints of interacting $f(Q,\mathcal{T})$ gravity in FRW Universe

TL;DR

This paper explores a modified gravity model, $f(Q, au)$, in a flat FRW universe, constraining it with observational data to explain cosmic acceleration without dark energy.

Contribution

It introduces a specific linear form of $f(Q, au)$ gravity, constrains model parameters with recent observational data, and demonstrates its viability as an alternative to $\\Lambda$CDM.

Findings

The model shows a transition from deceleration to acceleration.

Observational data constrains the model parameters effectively.

The model aligns with current cosmological diagnostics.

Abstract

This work investigates the dynamical evolution of the universe within the framework of symmetric teleparallel $f(Q,\mathcal{T})$ gravity, where $Q$ is the non-metricity scalar and $\mathcal{T}$ is the trace of the energy-momentum tensor. We consider a spatially flat Friedmann-Robertson-Walker (FRW) metric and explore a specific functional form $f(Q,\mathcal{T}) = \alpha Q + \beta \mathcal{T}$ to derive the gravitational field equations. To characterize the late-time cosmic acceleration, we utilize a model-independent approach by adopting a particular Hubble parameter $H(z)$ parametrization. The model parameters are constrained using the latest observational datasets, including the Hubble ($H(z)$) measurements and Pantheon+ samples. Our results indicate a transition from a decelerated to an accelerated expansion phase. We further examine the physical viability of the model through various cosmological diagnostics such as energy density, the equation of state parameter and thermodynamic properties. The analysis demonstrates that $f(Q,\mathcal{T})$ gravity provides a consistent alternative to the $\Lambda$CDM model in explaining the current accelerated expansion of the universe.