Gravitação unimodular na teoria de Brans-Dicke.

• Ano de defesa: 2022
• Autor(a) principal: Almeida, Alexandre Magno Rodrigues
• 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; Gravitação; Unimodular; Brans-Dicke; subject.br-rjbn; Física
• Link de acesso: http://repositorio.ufes.br/handle/10/16573

We propose a unimodular version of the Brans–Dicke theory designed with a constrained Lagrangian formulation. The resulting field equations are traceless and the theory fails to be invariant under general diffeomorphisms. The vacuum solutions in the cosmological background reproduce the corresponding solutions of the usual Brans–Dicke theory but with a cosmological constant term. A perturbative analysis of the scalar modes is performed and stable and unstable configurations appear, in contrast with the Brans–Dicke case for which only stable configurations occur. On the other hand, tensorial modes in this theory remain the same as in the traditional Brans–Dicke theory.