Transiently accelerating cosmological model with Gong-Zhang parametrization in $f(T)$ teleparallel gravity

TL;DR

This paper explores a $f(T)$ gravity model with Gong-Zhang dark energy parametrization, showing it predicts a transient acceleration phase consistent with observations and thermodynamic laws.

Contribution

It introduces a specific $f(T)$ model with Gong-Zhang parametrization, analyzing its cosmic evolution and observational viability with Bayesian methods.

Findings

Model predicts transient cosmic acceleration followed by future deceleration.

The model exhibits quintessence-like behavior at present.

Thermodynamic analysis confirms the model's viability.

Abstract

We present the cosmic expansion scenario in the framework of $f(T)$ gravity by employing a dark energy equation of state (EoS) parameter. Specifically, we proceed with the power-law form of the function $f(T) = \alpha$$(-T)^{n}$, in conjunction with the Gong-Zhang parametrization of the dark energy EoS. We derive the expansion rate in terms of the redshift for the considered model, providing deeper insights into the underlying cosmic dynamics. The model is further utilized to explore the expansion history of the universe and the evolution of several cosmological parameters. By using the Bayesian methods based on the $\chi^{2}$-minimization technique, the median values of the model parameters are determined for the cosmic chronometer (CC) and joint (CC+Pantheon) datasets. The evolution of the deceleration parameter, energy density, pressure, EoS parameter and the energy conditions for dark energy is analyzed in detail. The model captures the observed acceleration as a transient phenomenon, followed by future deceleration. Additionally, the nature of both geometrical and dynamical diagnostics robustly indicates a quintessence-like behavior at the present epoch. Finally, the thermodynamic viability of the model is confirmed through the generalized second law of thermodynamics and the estimated age of the universe further supports the model's compatibility with astronomical observations.