Comparison of $f(R,T)$ Gravity with Type Ia Supernovae Data

TL;DR

This paper explores $f(R,T)$ gravity models, especially those with $f_2(T) o T^{-1}$, demonstrating they can replicate late-time cosmic acceleration and fit Type Ia supernovae data as well as or better than standard models.

Contribution

It introduces specific $f(R,T)$ gravity functions that naturally produce late-time acceleration and shows these models fit supernova data comparably or better than standard cosmology.

Findings

$f(R,T)$ models with $f_2(T) o T^{-1}$ produce exponential late-time growth.

These models fit Type Ia supernovae data as well or better than the standard model.

The models achieve acceleration without increasing the number of free parameters.

Abstract

The expansion of the universe in $f(R,T)$ gravity is studied. By focusing on functions of the form $f(R,T)=f_1(R)+f_2(T)$, we assert that present day acceleration can be achieved if the functional form of $f_2(T)$ either grows slowly or falls as a function of $T$. In particular, we demonstrate that when $f_2(T) \propto T^{-1}$, the universe transitions to exponential growth at late times, just as it does in the standard cosmological model. A comparison of predictions of this model, with Type Ia supernovae shows that this model fits the data as well or even slightly better than the standard cosmological model without increasing the number of parameters.