Inflationary theory in anisotropic universes

Author(s)

Thiago dos Santos Pereira

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Física (IF/SBI)
• Defense date: 2008-12-18

Examining board members

Luis Raul Weber Abramo; Fernando Tadeu Caldeira Brandt; George Emanuel Avraam Matsas; Marcelo Jose Rebouças; Victor de Oliveira Rivelles

• Advisor: Luis Raul Weber Abramo

Abstract

In this work we generalize the standard theory of cosmological perturbations to the case of homogeneous and anisotropic universes described by a Bianchi I spacetime metric. As an application of this theory we investigate the predictions of an inflationary anisotropic phase, both at the classical and quantum level. After discussing the evolution of the background spacetime, we solve and quantize the perturbation equations in order to predict the power spectra of the curvature perturbations and gravity waves at the end of inflation. Our results show that the main features of an early anisotropic phase are: (1) a dependence of the spectra on the direction of the modes, (2) a coupling between curvature perturbations and gravity waves, and (3) the fact that the two gravity waves polarisations do not share the same spectrum on large scales. All these effects are significant only on large scales and die out on small scales where isotropy is recovered. Finally, our results depend on a characteristic scale that can, but a priori does not have to, be tuned to some observable scale. (AU)