Quantum signatures of the Inflationary scenario in the Cosmic Microwave Background radiation

Abstract

As of today, we are in the golden era of Cosmology. More and more data is being collected from the Cosmic Microwave Background (CMB) radiation, thanks to the technological advancement of the last years. This data would help to probe the inflationary models, whose differences have been investigated beyond Gaussianities. However, the experimental access to those is not granted. With the present thesis we wish to set the basis for an alternative approach to probe inflationary models, considering uniquely Gaussian correlator as linked to possible observables. We propose an extension of already existing Inflationary perturbations models, which adds new initial conditions to the \textit{classical} Boltzmann problem of the universe. Relying on a process of decoherence due to an interaction between the adiabatic perturbations and an environment (e.g. isocurvature perturbations), whose information will be ignored, we might seed two new \textit{classical stochastic variables}, whose contribution comes in the acoustic peaks of the CMB and could be detected in terms of a phase shift in the profile of the angular power spectrum for the photon temperature fluctations.\\ Further, the assumption of a decoherence process connects the classical stochastic behaviour of the Large Scale Structure to the quantum framework offered by inflation, explaining causally its stochastic behaviour as arising from the initial quantum state.