The recent analysis of data collected by the Planck satellite constrains inflationary scenarios through the observational testing of specific primordial bispectra predicted by different inflationary theories. When considering an inflationary scenario, quantum fluctuations of primordial field(s), occurred during inflation and stretched to macroscopic scales, induced fluctuations in the space-time metric. These last fluctuations can be classified as scalar, vector and tensor fluctuations and left a characteristic signature on the Cosmic Microwave Background (CMB). Specifically, the cubic interactions experienced by these fields generated primordial bispectra, which are the Fourier counterparts of three-point expectation values. These primordial bispectra are linked to non-Gaussianities in the statistics of the CMB anisotropies. For this reason, the theoretical study of primordial bispectra predicted by inflationary models is essential for the comprehension of the physics of the very early Universe. The model of Solid Inflation shows differentiating features from other inflationary models such as non-decaying vector perturbations, a mass for gravitational waves and a model-specific scalar bispectrum with non-trivial angular dependence. The aim of this thesis is to integrate the study of essential theoretical elements to augment the range of computed primordial bispectra within the model of Solid Inflation. Specifically, six bispectra involving scalar, vector, tensor perturbations predicted by the model of Solid Inflation will be presented. These bispectra have never appeared in literature and show an enhancement represented by the minimum number of e-foldings at which the CMB modes left the horizon.

The model of Solid Inflation and its outcomes

Marranconi, Martino
2017/2018

Abstract

The recent analysis of data collected by the Planck satellite constrains inflationary scenarios through the observational testing of specific primordial bispectra predicted by different inflationary theories. When considering an inflationary scenario, quantum fluctuations of primordial field(s), occurred during inflation and stretched to macroscopic scales, induced fluctuations in the space-time metric. These last fluctuations can be classified as scalar, vector and tensor fluctuations and left a characteristic signature on the Cosmic Microwave Background (CMB). Specifically, the cubic interactions experienced by these fields generated primordial bispectra, which are the Fourier counterparts of three-point expectation values. These primordial bispectra are linked to non-Gaussianities in the statistics of the CMB anisotropies. For this reason, the theoretical study of primordial bispectra predicted by inflationary models is essential for the comprehension of the physics of the very early Universe. The model of Solid Inflation shows differentiating features from other inflationary models such as non-decaying vector perturbations, a mass for gravitational waves and a model-specific scalar bispectrum with non-trivial angular dependence. The aim of this thesis is to integrate the study of essential theoretical elements to augment the range of computed primordial bispectra within the model of Solid Inflation. Specifically, six bispectra involving scalar, vector, tensor perturbations predicted by the model of Solid Inflation will be presented. These bispectra have never appeared in literature and show an enhancement represented by the minimum number of e-foldings at which the CMB modes left the horizon.
2017-12
117
Early Universe, Cosmic Microwave Background, Solid Inflation, primordial bispectra, non-Gaussianities, vector perturbations, non-trivial angular dependence
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.12608/25110