Cosmological implications of the constant jerk parameter in $f(Q,T)$ gravity theory

TL;DR

This paper explores a modified gravity model involving non-metricity and trace coupling, using a constant jerk parameter to analyze cosmic acceleration and constrain the model with observational data.

Contribution

It introduces a specific $f(Q,T)$ gravity model with a constant jerk assumption and constrains it using multiple cosmological datasets, providing insights into cosmic acceleration.

Findings

The model indicates an accelerating universe consistent with observations.

Constraints from data support the validity of the constant jerk $f(Q,T)$ model.

The $Om(z)$ diagnostic effectively differentiates dark energy theories.

Abstract

This study delves into modified gravity theories that are equivalent to General Relativity but involve the torsion or non-metricity scalar instead of the curvature scalar. Specifically, we focus on $f(Q,T)$ gravity, which entails an arbitrary function of the non-metricity scalar $Q$ non-minimally coupled to the trace of the stress-energy tensor $T$. We investigate the functional form $f(Q,T)=f(Q)+f(T)$, where $f(Q) =Q+\alpha\,Q^2$ represents the Starobinsky model in $f(Q)$ gravity and $f(T)=2\,\gamma\,T$, with $\alpha$ and $\gamma$ are constants. To obtain solutions for the Friedmann equations, we introduce the concept of a constant jerk and employ its definition to trace the evolution of other kinematic variables, including the deceleration parameter, energy density, EoS parameter, and various energy conditions. These analyses serve to validate the proposed model. We constrain our constant jerk model using the most available Pantheon set of data, the Hubble set of data, and the BAO set of data. Further, we employ $Om(z)$ diagnostic as a means to differentiate between different theories of dark energy. Throughout our examination, all cosmological parameters under scrutiny consistently indicate an accelerating Universe.