On the torsion effects of a relativistic spin fluid in early cosmology

TL;DR

This paper explores how torsion in Einstein-Cartan theory influences early universe cosmology, focusing on homogeneous spin fluids and their effects on singularity avoidance and cosmic acceleration.

Contribution

It introduces new solutions for a relativistic spin fluid with axial current in Einstein-Cartan theory, analyzing their impact on early universe dynamics.

Findings

Certain solutions avoid singularities

Some solutions lead to accelerated expansion

Properties depend on source parameter relations

Abstract

In this work we investigate the effects of torsion in the framework of Einstein-Cartan theory in early cosmology. We study solutions for a homogeneous and isotropic relativistic Weyssenhoff spin fluid with dynamical timelike axial current, also homogeneous and isotropic. The general solutions can mostly be described by means of three particular solutions. The properties of these solutions (such as singularity avoidance and primordial or late accelerated expansion) are analysed and depend on the relations between the source parameters.