Hubble-Induced Phase Transition: Reheating with Gauge Fields

Giorgio Laverda


Reheating is one of the greatest unknowns in the history of the Universe. In our scenario, a spontaneous symmetry breaking mechanism allows for the non-perturbative production of gauge fields in the early Universe, thus realising reheating after inflation. The key element of such process is a non-minimal coupling to curvature that triggers a tachyonic phase (the so-called Hubble-induced phase transition). I will present both an analytical analysis of the initial tachyonic regime and a lattice simulation of the full non-linear dynamics in the case of a spectator scalar field coupled to a U(1) gauge field. Possible characteristic signatures of the model will be discussed, together with its application and extension to the symmetry groups of the standard model.