Lorenzo Sorbo — Axions, U(1) gauge fields and inflation: an overview

Lorenzo Sorbo (UMass Amherst)

This is an overview talk about the role that axion-like degrees of freedom might play during inflation. In the first part of the talk I will review how such degrees of freedom are especially good inflaton candidates, courtesy the radiative stability of their potential. Then I will move on to study the effects of the interaction of axion-like inflatons with U(1) gauge fields. Such interactions lead to the generation of a chiral bath of gauge quanta during inflation, which in turn leads to a very rich phenomenology. I will review several of those signatures, paying special attention to the complicated (and still poorly understood) dynamics that emerges when the gauge quanta strongly backreact on the inflating background.