Extended inflation with nonminimally coupled inflaton field

Abstract

An extended inflation model, in which the inflaton field is nonminimally coupled to the gravity, is discussed. It is shown that the nucleation rate of bubbles, during a phase transition in the inflaton field, can increase as the transition proceeds for a wide range of parameters of the inflaton potential. The bounce action for three possible cases—the strong gravity regime, the thick-walled Coleman-De Luccia bubbles and the thin-walled bubbles—is evaluated. The resulting bubble distribution for all the cases is shown to be in conformity with cosmological constraints for ω<500.