Modelo cosmológico do tipo Kantowski-Sachs com gás de Chaplygin generalizado

Abstract

In this dissertation we study the dynamics of an Universe described by an anisotropic and homogeneous cosmological model of the Kantowski-Sachs type, where the material content is the radiation fluid and a Chaplygin gas. The latter representing the dark energy, which is the source of the accelerating expansion process. Using the Misner’s parametrization we rewrote the metric in terms of the scale factor a(t) and a parameter b(t), which is associated with the anisotropy. By resolving the Einstein’s equations, we analyzed how the changes in the parameters associated with the material content and the inicial conditions of the Universe affects the dynamics of a(t) and b(t). We noticed the existence of Big Crunch type solutions in which the Universe stays anisotropic at any stage of evolution, we also noticed the existence of expansive solutions in which the process of isotropization occurs and the Universe become isotropic at some point. By become isotropic the expansive solutions can represent the current Universe.