Hierarchical Axion Inflation

Abstract

We propose a new field theory mechanism for generating an effective trans-Planckian decay constant from sub-Planckian ones. Using the minimal two axions and a hierarchy between two axion decay constants is sufficient for realizing inflation through non-perturbative effects only and with minimal tuning. The inflationary motion is kept entirely within a sub-Planckian domain. We outline possible strategies of embedding the model in a string theory setup.

Comments: REVTeX, 5 pages, 2 figures, added refs, changed the numerical parameter values of the stringy example, removed ED1's from the superpotential