HET seminar: Mauro Pieroni

Speaker: Mauro Pieroni

Title: Universality classes for inflation and primordial GW from pseudoscalar inflation

Abstract: My seminar is divided in two parts: In the first part of my seminar I propose a classification of inflationary models by using the most basic property of inflation: the approximate scaling invariance. This framework relies on the possibility of describing inflation in terms of a renormalization group equation. The slow rolling regime in this context is interpreted as the slow evolution close to a fixed point. In this framework we can thus explain in part the universality observed in the predictions of a certain number of inflationary models. In the second part of my seminar I discuss the possibility of generating an observable gravitational wave (GW) background by coupling a pseudoscalar inflaton to some abelian gauge fields. The analysis is performed by dividing inflationary models into universality classes. One of the most promising scenarios is Starobinsky-like inflation, which may lead to observable signatures both in direct GW detectors as well as in upcoming CMB detectors. The complementarity between CMB and direct GW detection may be used to extract informations on the microphysics of inflation.