Some cosmological models coming from gravitational theories having torsional degrees of freedom

TL;DR

This paper explores cosmological models derived from gravitational theories with torsional degrees of freedom, incorporating characteristic classes into the Einstein-Hilbert action, leading to new insights beyond standard general relativity.

Contribution

It introduces a framework for including characteristic classes in gravitational theories with torsion and applies it to cosmological models using the FLRW metric.

Findings

Explicit expressions for contortion and torsion forms derived.

Cosmological scenarios analyzed with flat FLRW metric and ideal fluid.

New models extend general relativity by incorporating torsion effects.

Abstract

In this work we consider gravitational theories in which the effect of coupling characteristic classes, appropriately introduced as operators in the Einstein-Hilbert action, has been taken into account. As it is well known, this approach strays from the framework of general relativity since it results in theories in which torsion can be present. We consider here all the characteristic classes that are consistent with a four-dimensional space-time manifold. Then, we present explicit expressions for the contortion $1$-form and torsion $2$-form that can be obtained under general conditions in various cases of interest. Additionally, we use the same framework to study cosmological scenarios that are obtained mainly by selecting the flat FLRW metric and an ideal fluid.