The cosmological model in $ f(R,T^\phi) $ gravity with Scalar Field conformity

TL;DR

This paper explores a generalized $f(R,T^\phi)$ gravity model with a scalar field, showing a universe with no singularities, eternal expansion, moderate inflation, and late-time acceleration consistent with observations.

Contribution

It introduces a new $f(R,T^\phi)$ gravity model with a specific Hubble parameter parametrization, analyzing its physical features and observational consistency.

Findings

No space-time singularity in the model

Universe undergoes eternal expansion leading to Big Freeze

Model aligns with observational data like Hubble and supernovae datasets

Abstract

The homogeneous and isotropic cosmological model in generalized $ f(R,T^\phi) $ theories associated with scalar field is discussed, which is motivated by the $ f(R,T) $ theory of gravity studied by Harko et al. \cite{Harko:2011kv, Harko:2014pqa}. The $ f(R,T^\phi) $ gravity can be explained as $ f(R,T) $ gravity with a self-interacting scalar field $ \phi $, where $ T^\phi $ is the trace of the energy-momentum tensor. The parametrization of Hubble parameter $ H(t) $ is taken as $ \alpha-\beta e^{-\gamma t} $, where $ \alpha $, $\beta$ and $\gamma$ are arbitrary constants such that $ \alpha, \gamma>0 $ and $ \beta<0 $. The model shows no space-time singularity and the expansion of the universe will continue forever, i.e., the future scenario of the universe attains Big Freeze. The model predicts the moderate inflationary scenario at the time of the evolution of the universe and it is consistent with $ \Lambda $CDM in late times. The consistency of the model has also been examined using recent observational Hubble dataset and supernovae dataset. Finally, the physical features of the model have been discussed in some detail.