Squared torsion $f(T,\mathcal{T})$ gravity and its cosmological implications

TL;DR

This paper introduces a new modified gravity theory coupling torsion and energy-momentum trace, explores its cosmological implications, and fits it to observational data to explain late-time acceleration.

Contribution

It proposes a novel $f(T,\mathcal{T})$ gravity model with a specific functional form and analyzes its cosmological behavior and observational viability.

Findings

The model exhibits a transition from deceleration to acceleration.

The effective dark sector behaves like quintessence.

Observational data constrains model parameters effectively.

Abstract

We present the coupling of the torsion scalar $T$ and the trace of energy-momentum tensor $\mathcal{T}$, which produces new modified $f(T,\mathcal{T})$ gravity. Moreover, we consider the functional form $f(T,\mathcal{T}) =\alpha \mathcal{T}+\beta T^2$ where $\alpha$ and $\beta$ are free parameters. As an alternative to a cosmological constant, the $f(T,\mathcal{T})$ theory may offer a theoretical explanation of the late-time acceleration. The recent observational data to the considered model especially the bounds on model parameters is applied in detail. Furthermore, we analyze the cosmological behavior of the deceleration, effective equation of state and total equation of state parameters. However, it is seen that the deceleration parameter depicts the transition from deceleration to acceleration and the effective dark sector shows a quintessence-like evolution.