Regimes acelerados em modelos cosmológicos 2D e 3D

Abstract

Resumo: Apresentamos aqui um estudo das solucoes cosmologicas de tres modelos de gravitacao em dimensoes reduzidas: a Relatividade Geral e utilizada nos modelos 3D; as teorias propostas por Jackiw-Teitelboim e Callan et al sao utilizadas nos modelos 2D. A Termodinamica Relativistica modela as fontes em todos os cenarios estudados. A equacao de van der Waals (uma equacao de estado nao barotropica) e usada na descricao do fluido cosmologico no caso 2D. Enfatizamos o estudo de transicoes de regimes acelerado para desacelerado (da era inflacionaria para a era da materia) , e desacelerado para acelerado (da era da materia para o universo atual). Essas transicoes sao analogas as existentes nos modelos cosmologicos realistas em 4D.

Abstract: In this work we present an analysis of the cosmological solutions for three gravitational models in lower dimensions: the theory of General Relativity is used in the 3D formulations; the models proposed by Jackiw-Teitelboim and Callan et al appear in the 2D chse. The theory of Relativistic Thermodynamics furnishes the sources contributions in all scenarios. The van der Waals equation of state (a nonbaratropic equation) is used for the description of the cosmological fluid in the 2D formulations. We focus mainly on the analysis of accelerated-decelerated transitions (from the inflationary period to the matter era), and decelerated-accelerated (from the matter era to the present universe) ones. Those transitions are analogous to the ones present in the 4D realistic cosmolgical models.