The relation between Geometry and Matter in classical and quantum Gravity and Cosmology

TL;DR

This thesis explores the interplay between geometry and matter in classical and quantum gravity, focusing on cosmological models with scalar fields and the spinfoam approach to Loop Quantum Gravity.

Contribution

It introduces cosmological models with phantom and scalar fields for super-accelerated scenarios and analyzes face amplitudes in spinfoam models for quantum gravity.

Findings

Cosmological models with phantom and scalar fields can explain super-acceleration.

Analysis of face amplitudes advances understanding of quantum gravity transition amplitudes.

The work provides insights into the relation between geometry and matter in both classical and quantum regimes.

Abstract

The present thesis is divided into two main research areas: Classical Cosmology and (Loop) Quantum Gravity. The first part concerns cosmological models with one phantom and one scalar field, that provide the `super-accelerated' scenario not excluded by observations, thus exploring alternatives to the standard LambdaCDM scenario. The second part concerns the spinfoam approach to (Loop) Quantum Gravity, which is an attempt to provide a `sum-over-histories' formulation of gravitational quantum transition amplitudes: the research here presented focuses on the face amplitude of a generic spinfoam model for Quantum Gravity.