Spectral distortions of the cosmic microwave background and small-scale gravitational waves as new windows on the Early Universe

Tagliazucchi, Matteo (2023) Spectral distortions of the cosmic microwave background and small-scale gravitational waves as new windows on the Early Universe. [Laurea magistrale], Università di Bologna, Corso di Studio in Physics [LM-DM270]
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Abstract

In this thesis, we explore constraints which can be put on the primordial power spectrum of curvature perturbations beyond the scales probed by anisotropies of the cosmic microwave background and galaxy surveys. We exploit present and future measurements of CMB spectral distortions, and their synergy with CMB anisotropies, as well existing and future upper limits on the stochastic background of gravitational waves. We derive for the first time phenomenological templates that fit small-scale bumps in the primordial power spectrum generated in multi-field models of inflation. By using such templates, we study for the first time imprints of primordial peaks on anisotropies and spectral distortions of the cosmic microwave background and we investigate their contribution to the stochastic background of gravitational waves. Through a Monte Carlo Markov Chain analysis we infer for the first time the constraints on the amplitude, the width and the location of such bumps using Planck and FIRAS data. We also forecast how a future spectrometer like PIXIE could improve FIRAS boundaries. The results derived in this thesis have implications for the possibility of primordial black holes from inflation.

Abstract
Tipologia del documento
Tesi di laurea (Laurea magistrale)
Autore della tesi
Tagliazucchi, Matteo
Relatore della tesi
Correlatore della tesi
Scuola
Corso di studio
Indirizzo
THEORETICAL PHYSICS
Ordinamento Cds
DM270
Parole chiave
cosmology,cmb,spectral distortions,gravitational waves,inflation,primordial power spectrum,small-scale bumps,anisotropies
Data di discussione della Tesi
24 Febbraio 2023
URI

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