Dinâmica cosmológica para modelos com interações não-lineares no setor escuro

• Ano de defesa: 2012
• Autor(a) principal: Bacalhau, Anna Paula Ramos
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal do Espírito Santo; BR; Mestrado em Física; Centro de Ciências Exatas; UFES; Programa de Pós-Graduação em Física
• Palavras-chave em Português: Cosmologia; Matéria escura (Astronomia); Energia escura (Astronomia); Sistemas dinâmicos diferenciais; Supernovas; Física; 53
• Link de acesso: http://repositorio.ufes.br/handle/10/7439

We consider a set of non-linear interactions between dark matter and dark energy which comprises couplings proportional to products of (powers of) the energy densities of both dark components and of the total energy. We demonstrate that under such conditions the final state of the Universe may differ substantially from that of the standard ?CDM model. In particular, the ratio of the energy densities of dark matter and dark energy may approach a stable finite value or oscillate about such a value. Stationary solutions of this type require a phantom-type “bare”equation of state of the dark energy which, however, does not lead to a big-rip singularity. A corresponding analytic solution for a particular case is shown to be consistent with the supernova type Ia (SNIa) data from the Union2 set. For a broader class of interactions, a dynamical system analysis classifies stationary points with emphasis on their potential relevance for the coincidence problem