Phyiscs and cosmology of dark energy

This thesis is structured as follows: in the first Chapter we will review the state of art of dark energy and the basic equations that will be used in the next Chapters; in the second Chapter we will introduce dark energy modeled as a scalar field with a potential and interactions; taking into account both the modified background evolution and the growth of linear perturbations, the third Chapter presents the constraints on the main parameters in an uncoupled dark energy model from galaxy surveys, while the fourth Chapter analyses the effect of dark energy on the Cosmic Microwave Background radiation in a more general coupled model; in the fifth Chapter we will present the first step beyond linearity, investigating the third order moment of the galaxy distribution in several dark energy models; the sixth Chapter completes the non-linear analysis with a full numerical treatment in an N-body code, where clustering properties such as mass function and density profiles are derived; the seventh Chapter concludes with some hints about the backreaction of dark energy perturbations and prospects. In all the thesis we will use h¯ = c = 1.