Cosmologia inflacionária via campos escalares.

Abstract

In the theory of inflationary cosmology, which has as reference the observed universe, the gravitation force is always attractive. There was never any firm evidence of "anti-gravity" in the laboratory or stellar systems/galaxies. But this was not necessarily always so, and a possible solution to the problem of the origin of the Universe expansion, is we had a time where at least effectively, gravitation has been disgusting. Indeed, the Friedmann equations give an important relationship between pressure p and energy density ρ, since the sign of the acceleration given this for her. This opens up the possibility of there having been some time in which the universe's expansion was accelerated. This is the basic concept of the inflationary era. In this work we will insert scalar fields in Friedmann equations using the energy-momentum tensor for the simplest example of a scalar field thus obtaining the energy density and pressure of a particle. This done, we can obtain the equation of motion of the particle to analyze the temporal evolution of the scalar field known as ínflaton, responsible for the early inflationary phase. Possession of the equation of motion of the particle, we use the approximation method slow-roll, densities of potential energy e cos potential to determine the scalar field and the scale factor. With the scale factor can determine the deceleration parameter for the two cases presented, and concludes that these potential energy densities may represent a model Universe that is expanding rapidly, which is in agreement with current cosmological observations.