Cosmological consequences in the framework of generalized Rastall theory of gravity

TL;DR

This paper explores the cosmological implications of generalized Rastall gravity, demonstrating a non-singular early universe, equivalence to particle creation mechanisms, and a complete cosmic evolution from inflation to late-time acceleration.

Contribution

It introduces a cosmological model within generalized Rastall gravity that exhibits a non-singular emergent universe and aligns with thermodynamic principles, extending understanding of alternative gravity theories.

Findings

Non-singular emergent universe scenario at early times

Equivalence to particle creation in Einstein gravity

Complete cosmic evolution from inflation to acceleration

Abstract

The paper deals with generalized Rastall theory of gravity and its cosmological consequences in the background of homogeneous and isotropic flat FLRW model with perfect fluid as the matter context. The model shows a non singular era (emergent scenario) at the early phase of expansion for a particular choice of the Rastall parameter. Also the model finds to be equivalent to the particle creation mechanism in Einstein gravity in the framework of non-equilibrium thermodynamics. Universal thermodynamics is briefly presented and it is found that the entropy function in Rastall theory is the usual Bekenstein entropy and there is no correction to it. Finally, a complete cosmic history starting from inflation to late time acceleration is presented for suitable choices of the Rastall parameter.