Seminar

The Initial State of a Primordial Anisotropic Stage of Inflation

By
Masato Minamitsuji (Lisbon, CENTRA)
Date
Place
Aula 507
seminar ICCUB
Large scale anomalies discovered in recent CMB measurements suggest that our Universe may have a highly anisotropic primordial stage. In this talk, assuming that our universe was very anisotropic at its beginning, we argue what can be a realistic initial state of primordial fluctuations of a massless scalar field, which would be sources of the density perturbations.

First, we review that the singularity-free branch of planar Kasner-de Sitter universe, which has been thought as a good candidate of the isotropizing Bianchi I universe in the literature, suffers pathological behaviors, such as the divergence of the primordial fluctuations in the planar direction and the unpredictability of quantum state because of the hidden timelike singularity behind the past horizon.

Then, based on the landscape picture of vacua with stabilized compact directions, we consider the possibility that the Kasner de Sitter universe is an outcome of transdimensional quantum tunneling from a regular mother universe with stabilized spatial directions. We argue how the nature of the power spectrum of the primordial fluctuations is modified when they are quantized in the new vacuum.