Transformação conforme e Modelo Cosmológico com spin na teoria de Einstein-Cartan

Abstract

In gravitation, it is possible to write metric tensor using a conformal factor. In this sense, conformal symmetry is an important feature in Cosmology. We firstly present a useful study on this subject, along with several techniques of calculating linear and quadratic terms on curvature. Next, we investigate the effects of torsion in the framework of Einstein-Cartan theory in early cosmology. We study solutions for a homogeneous and 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.