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

Understand

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.