Light scalars and the cosmos: Nambu-Goldstone and otherwise

Abstract

This talk focuses on the role of light scalars in cosmology, both Nambu-Goldstone bosons and pseudo moduli. The former include QCD axions, which might constitute the dark matter, and more general axions, which, under certain conditions, might play the role of inflatons, implementing natural inflation. The latter are the actors in (generalized) hybrid inflation. They rather naturally yield large field inflation, even mimicking chaotic inflation for suitable ranges of parameters.