|| Title: Constraining axion inflation with gravitational waves from preheating ||
Abstract: Models in which a pseudoscalar inflaton (axion) is coupled to the Chern-Simons density are of particular theoretical and phenomenological interest. The coupling between the inflaton and some (Abelian) gauge fields induces an instability which gives rise to a wide range of potentially observable signatures. After reviewing the key features of these models and their phenomenology, I discuss the impact of the different parameters on the efficiency of preheating. In particular, I explain how gravitational waves from preheating set the strongest constraints on the inflaton’s possible axial coupling to gauge fields. ||