Self-similarity in a Kantowski-Sachs universe with a string cloud

Abstract

We study a cosmological model with very simple solutions characterized by string clouds. Assuming self-similar symmetry for a Kantowski-Sachs spacetime we study the gravitational effects of the cosmic strings. It is also assumed that the primitive universe enters in a false vacuum-dominated era, accelerating the expansion in a time period of the order of $10^{-35}$ {\rm sec} (a phase transition), satisfying all the energy conditions. Finally, we examine the possibility that in the last stages of this evolution, the geometry of the universe could be flat.