title: Warm Little Inflaton.
abstract: We show that inflation can naturally occur at a finite temperature T>H that is sustained by dissipative effects, when the inflaton field corresponds to a pseudo Nambu-Goldstone boson of a broken gauge symmetry. Similar to the Little Higgs scenarios for electroweak symmetry breaking, the flatness of the inflaton potential is protected against both quadratic divergences and the leading thermal corrections. We show that, nevertheless, nonlocal dissipative effects are naturally present and are able to sustain a nearly thermal bath of light particles despite the accelerated expansion of the Universe. As an example, we discuss the dynamics of chaotic warm inflation with a quartic potential and show that the associated observational predictions are in very good agreement with the latest Planck results. This model constitutes the first realization of warm inflation requiring only a small number of fields; in particular, the inflaton is directly coupled to just two light fields.
authors: Departamento de Física Teórica y del Cosmos, Universidad de Granada, Granada-18071, Spain.
authors: Mar
authors: M
authors: Bastero-Gil
authors: School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3FD, United Kingdom.
authors: Arjun
authors: A
authors: Berera
authors: Departamento de Física Teórica, Universidade do Estado do Rio de Janeiro, 20550-013 Rio de Janeiro, RJ, Brazil.
authors: Rudnei O
authors: RO
authors: Ramos
authors: Departamento de Física da Universidade de Aveiro and CIDMA, Campus de Santiago, 3810-183 Aveiro, Portugal.
authors: João G
authors: JG
authors: Rosa