Speaker: Pablo Soler Gomis, University of Wisconsin-Madison
Abstract: Axions, enjoying an approximate shift symmetry, are some of the most popular inflaton candidates in the market. Via mixing and alignment, they seem to yield viable models of (natural) large field inflation, with corresponding trans-Planckian inflaton excursions. I will describe in this talk how, however, generic considerations of quantum gravity prevent such mechanisms to generate the large field ranges required for successful inflation, thus putting the whole natural inflation program in jeopardy. I will also critically address possible loopholes of this “no-go” theorem and attempts to overcome it.