Late time phantom characteristic of the model in $f(R,T)$ gravity with quadratic curvature term

TL;DR

This paper introduces a new $f(R,T)$ gravity model with higher-order curvature terms, constrained by observational data, which successfully describes the transition from early deceleration to late-time acceleration in the universe.

Contribution

It proposes a novel $f(R,T)$ gravity framework with quadratic curvature and trace coupling, and constrains it using recent cosmological datasets to explain cosmic acceleration.

Findings

Model exhibits early deceleration and late-time acceleration.

Transition redshift between 1.10 and 1.15.

Efficiently models dark energy within $f(R,T)$ gravity.

Abstract

We propose a novel cosmological framework within the $f(R,T)$ type modified gravity theory, incorporating a non-minimally coupled with the higher order of the Ricci scalar ($R$) as well as the trace of the energy-momentum tensor ($T$). Therefore, our well-motivated chosen $f(R,T)$ expression is $ R + R^m + 2 \lambda T^n$, where $\lambda$, $m$, and $n$ are arbitrary constants. Taking a constant jerk parameter ($j$), we derive expressions for the deceleration parameter ($q$) and the Hubble parameter ($H$) as functions of the redshift $z$. We constrained our model with the recent Observational Hubble Dataset (OHD), $Pantheon$, and $ Pantheon $ + OHD datasets by using the analysis of Markov Chain Monte Carlo (MCMC). Our model shows early deceleration followed by late-time acceleration, with the transition occurring in the redshift range $1.10 \leq z_{tr} \leq 1.15$. Our findings suggest that this higher-order model of $f(R,T)$ gravity theory can efficiently provide a dark energy model for addressing the current scenario of cosmic acceleration.