Kaluza-Klein modes in hybrid inflation

Abstract

When one constructs specific models with a fundamental scale as low as the TeV scale, there arise many difficulties. In this Brief Report we examine hybrid inflation due to bulk scalar fields, which has been proposed to solve the problem of fine-tuning in producing density perturbations. We find that the Kaluza-Klein modes play significant roles, which enhance the speed of the phase transition and alter the reheating process. We also argue that a lower bound must be put to the fundamental scale in order to construct successful hybrid inflation due to bulk scalar fields.