Applications of the (3+1)-formalism of General Relativity to Cosmology

: A study of Hybrid Inflation and Spherical Collapse with quintessence

Abstract

This work deals with two different subjects of physical cosmology
joined together by the usage of the (3+1) formalism of General Relativiy and
the presence of a minimally coupled scalar degree of freedom. In the first
part, we show how the original Hybrid Inflation model in the large field regime
can generate a large value of the tensor to scalar perturbations ratio and we
perform the statistical analysis of the parameter space demonstrating the very
good possible agreement with observable data. In the second part, we study the
evolution of space-time in the surroundings of a spherical over-density of matter that asymptotically corresponds to the homogeneous and isotropic Universe filled with a quintessence scalar field. The numerical method proposed allows the complete ab initio study of the spherical collapse process and the study of the implication of quintessence on the formation of galaxy clusters.

Date of Award	17 Sept 2015
Original language	English
Awarding Institution	University of Namur
Supervisor	Andre Fuzfa (Supervisor), Timoteo Carletti (President), Sebastien CLESSE (Jury), Jean-Michel Alimi (Jury), Isabel Cordero-Carrión (Jury) & Eric Gourgoulhon (Jury)