Constraining the $f(R,T) = R + 2\lambda T$ cosmological model using recent observational data

TL;DR

This study constrains the $f(R,T) = R + 2 heta T$ cosmological model using recent observational data, demonstrating its viability in explaining accelerated cosmic expansion and stability across cosmic epochs.

Contribution

It provides the first comprehensive observational constraints on the $f(R,T)$ model with detailed analysis of cosmic parameters and stability, highlighting its potential as a viable alternative to dark energy models.

Findings

The universe is currently accelerating with $q_0=-0.64$.

Transition from deceleration to acceleration occurs at $z_{tr}=0.53$.

The model remains stable across cosmic evolution.

Abstract

In this paper, we consider a comprehensive investigation of the cosmological model described by $f(R,T) = R + 2\lambda T$ (where $\lambda$ represents a free parameter) in light of the most recent observational data. By constraining the model using $Hubble$ and $Pantheon$ datasets, we determine its compatibility with the observed behavior of the Universe. For this purpose, we adopt a parametric form for the effective equation of state (EoS) parameter. This parametric form allows us to describe the evolution of the EoS parameter with respect to redshift and investigate its behavior during different cosmic epochs. The analysis of the deceleration parameter reveals an accelerating Universe with a present value of $q_0=-0.64^{+0.03}_{-0.03}$, indicating the current phase of accelerated expansion. The transition redshift is found to be $z_{tr}=0.53^{+0.04}_{-0.03}$, marking the epoch of transition from deceleration to acceleration. We also analyze the evolution of important cosmological parameters including density parameter, pressure, effective EoS, and stability. These findings collectively demonstrate the viability of the $f(R,T)$ cosmological model as a robust candidate capable of engendering the requisite negative pressure, thereby efficiently propelling cosmic expansion. Moreover, the undertaken stability analysis underscores the model's stability within the broader cosmic landscape. By providing the best-fit values for the coupling parameter $\lambda$, this approach motivates and encourages further explorations into the extensive landscape of this model and its potential applications across diverse realms of cosmology and astronomy.