Modelos de energia escura com acoplamento não-mínimo ao campo escalar e quebra de simetria.

Abstract

In this work, we will study the properties of cosmological models with a non-minimal coupling of a scalar field with the geometry, with a screening mechanism, more specifically the symmetron mechanism, which makes the field active only in ambients of low matter density and times of accelerated expansion, like the inflation and the current cosmic acceleration period. We will see the simplest form of the model, to consider afterward that seeks to alleviate problems present in its original form. The dynamics of each potential will be investigated by the method of the dynamical system of autonomous first-order equations, where we can generate phase diagrams and compute important cosmological parameters. We will find that the two-field model can generate stable de Sitter solutions, useful to describe a persistent cosmic acceleration.