Non-minimal coupling inspires the Dirac cosmological model

TL;DR

This paper explores how a non-minimal coupling in the generalized Rastall theory can lead to a variable gravitational constant G, compatible with Dirac's hypothesis and capable of explaining the current accelerated expansion of the universe.

Contribution

It demonstrates that in GRT, a variable G can be linked to a non-minimal coupling, providing a new framework for cosmological modeling consistent with observations.

Findings

Variable G profiles can be derived from non-minimal coupling in GRT.

The model is compatible with Dirac's hypothesis on G variation.

The framework can account for the current accelerated universe.

Abstract

In the framework of the generalized Rastall theory (GRT), we study the ability of a non-minimal coupling between geometry and matter fields in order to provide a setting which allows for a variable G during the cosmic evolution. In this regard, the compatibility of this theory with Dirac hypothesis on the variations of G is investigated, and additionally, the possibility of obtaining the current accelerated universe is also addressed. In summary, our study indicates that, in GRT, having in hand the G profile, one may find the corresponding non-minimal coupling between the energy source and geometry and vise versa, in a compatible way with the current accelerated universe.