Ondas gravitacionais e o espectro de anisotropia tensorial na presença de neutrinos cosmológicos

• Ano de defesa: 2012
• Autor(a) principal: Santos, Jonas Floriano Gomes dos
• Orientador(a): Bernardini, Alex Eduardo de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Carlos
• Programa de Pós-Graduação: Programa de Pós-Graduação em Física - PPGF
• País: BR
• Palavras-chave em Português: Física; Cosmologia; Ondas gravitacionais; Neutrinos
• Área do conhecimento CNPq: CIENCIAS EXATAS E DA TERRA::FISICA
• Link de acesso: https://repositorio.ufscar.br/handle/20.500.14289/5045

In this work we have studied the evolution of primordial gravitational waves coupled to anisotropic stress tensor of cosmological neutrinos. As in a radiation dominated universe, in a universe dominated by radiation and matter the neutrinos can work as an effective dispersive medium for the gravitational waves, besides introduce small modifications over the tensor contribution to the cosmological microwave background anisotropy. Our results are obtained in a radiation-matter transition scenario (RMD), so that we contemplate modes that cross the horizon in the radiation era and matter era. Using the evolution variable kη, it was possible to write our solutions independent from the frequency of the wave. Our results ratify that CT l die out after l ∼ 100 with small modifications on the quadrupole term, CT 2 , due to the coupling to neutrinos and the inclusion of collision terms into the dynamical equations.