Abstract:
We will review our current understanding of reheating after inflation, including various aspects of the linear and
nonlinear dynamics of the inflaton field, such as parametric resonance, the generation of metric perturbations and the effects of the nonlinear evolution on the post-inflationary expansion history. We will also review the recent progress in the understanding of the non-perturbative dynamics of dark vector fields during reheating and whether they can play the role of dark matter in the late universe. Finally, we will discuss phenomenologically interesting models of gauge fields during inflation which can give rise to detectable gravitational wave signatures.
Speaker: Lorenzo Sorbo
Title: Reviving chaotic inflation with fermion production: a supergravity model
Room: 3024
Zoom: https://zoom.us/j/186024391
Host: Nemanja
Abstract:
Processes of particle production during inflation can increase the amplitude of the scalar metric perturbations. We show that such a mechanism can naturally arise in supergravity models where an axion-like field drives large field inflation. In this class of models one generally expects instanton-like corrections to the superpotential. We show, by deriving the equations of motion in models of supergravity with a stabilizer, that such corrections generate an interaction between the inflaton and its superpartner. This inflaton-inflatino interaction term is rapidly oscillating, and can lead to copious production of inflatinos during inflation, filling the Fermi sphere up to momenta much larger than the Hubble parameter. In their turn, those fermions source inflaton fluctuations, increasing their amplitude, and effectively lowering the tensor-to-scalar ratio for the model. This allows, in particular, to bring the model where the inflaton potential is quadratic (plus negligibly small instanton corrections) to agree with all existing observations.
Kwanzaa ends