Automorphic inflation

A framework of inflation is formulated based on symmetry groups and their associated automorphic functions. In this setting the inflaton multiplet takes values in a curved target space constructed from a continuous group Gand a discrete subgroup Gamma. The dynamics of inflationary models is essentially determined by the choice of the pair (G, Gamma) and a function Phi on the group G. Automorphic inflation provides a natural structure in which the shift symmetry of large field inflation arises as one of generators of Gamma. The model of j-inflation is discussed as an example of modular inflation associated with the special linear group. (C) 2015 The Author. Published by Elsevier B.V.