Cosmology from an exponential dependence on the trace of the energy-momentum tensor -- Numerical approach and cosmological tests

Abstract

In this paper, we present the cosmological scenario obtained from $f(R,T)$ gravity by using an exponential dependence on the trace of the energy-momentum tensor. With a numerical approach applied to the equations of motion, we show several precise fits and the respective cosmological consequences. As a matter of completeness, we also analyzed cosmological scenarios where this new version of $f(R,T)$ is coupled with a real scalar field. In order to find analytical cosmological parameters, we used a slow-roll approximation for the evolution of the scalar field. This approximation allowed us to derived the Hubble and the deceleration parameters whose time evolutions describe the actual phase of accelerated expansion, and corroborate with our numerical investigations. Therefore, the analytical parameters unveil the viability of this proposal for $f(R,T)$ in the presence of an inflaton field.