Anisotropic Cosmology with interacting Dark Energy in f(R,T) Gravity: A Data-Constrained & independent Approach

TL;DR

This study explores anisotropic cosmological models within $f(R,T)$ gravity, constraining parameters with observational data to demonstrate consistency with current cosmic acceleration and dark energy behavior.

Contribution

It introduces a data-constrained anisotropic $f(R,T)$ gravity model using a variable deceleration parameter and observational datasets, analyzing its viability and stability.

Findings

Model fits observational Hubble and supernova data well.

Reproduces transition from deceleration to acceleration consistent with $ ext{Λ}$CDM.

Effective EoS indicates a quintessence-like dark energy.

Abstract

In this work, we investigate the cosmological dynamics of an anisotropic Universe within the framework of $f(R,T)$ gravity by incorporating pressureless dark matter and the dark energy models. The analysis is carried out in a Bianchi type-I space-time, allowing us to capture possible deviations from isotropy and their evolution during cosmic expansion. A phenomenological reconstruction scheme based on a variable deceleration parameter is adopted to derive a redshift-dependent Hubble function. To establish observational viability, we constrain the free parameters of the model using a comprehensive statistical analysis that combines observational Hubble data and the Pantheon+ Type Ia supernova compilation. The resulting parameter space is tightly bounded, and the reconstructed expansion history exhibits strong consistency with current observational expectations. The model successfully reproduces the transition from an early decelerating phase to the present accelerated epoch, while asymptotically approaching a de Sitter-like regime. Further we analyzed the geometrical diagnostics, including the statefinder and $O_m$ diagnostics, which indicate a close correspondence with the standard $\Lambda$CDM scenario at late times. The behavior of the effective equation of state suggests a dynamically evolving dark energy component consistent with a quintessence-like regime. Additionally, the analysis of energy conditions confirms the physical admissibility of the model, whereas the stability investigation reveals the presence of classical instabilities at the perturbative level.