Aspects of preheating and Higgs cosmology

Resumen

In this thesis we explore several aspects of the out-of-equilibrium dynamics of the Universe after inflation. The first part of the thesis is focused on preheating: an explosive production of particles due to non-perturbative effects. We first present a fitting analysis of parametric resonance for chaotic inflation models. By using classical lattice simulations, we parametrize the main time scales, energy fractions, and field spectra, in terms of all circumstances and parameters. Preheating is also a powerful source of primordial gravitational waves (GW) in the early universe. We have parametrized the frequency and amplitude of the peaks in the GW spectra, as well as obtained predictions for the GW signal today. The second part of the thesis is focused on Higgs Cosmology. In particular, we have studied the post-inflationary decay of the Standard Model Higgs condensate. After inflation the Higgs oscillates, transferring most of its energy to gauge bosons via parametric resonance. We have studied this process with lattice simulations, and have characterized in detail the evolution of the Higgs and its decay products. We have obtained a generic formula for the Higgs decay time as a function of all unknowns, as well as studied the production of GW in this process. We have also studied the implications of a non-minimal Higgs-curvature coupling for vacuum stability after inflation. The thesis also provides a complete lattice formulation of scalar and gauge theories in an expanding universe.