Cosmic Inflation from String Axions

by Dr Susha Parameswaran (Liverpool University)

Monday 19 Dec 2016, 15:00 → 16:00 Europe/Rome

Aula Teorici (Dipartimento di Fisica e Astronomia)

Inflation, driven by a scalar field slowly rolling down a flat potential, is notoriously plagued by the eta problem, whereby quantum effects generically render the potential too steep. A very promising way to resolve this problem is if the inflaton is an axion field, whose potential is protected by a perturbative shift symmetry. However, the canonical models of axion inflation - "Natural Inflation" and "Axion Monodromy" - are now both in tension with observations and difficult to embed in a UV complete theory like string theory. I will discuss these challenges, and also a way to overcome them, with an inflationary mechanism beyond slow roll that is consistent with observations and that has distinctive signatures.