Preheating in New Inflation

TL;DR

This paper provides a comprehensive analysis of preheating in new inflation, revealing that the decay of the inflaton field occurs rapidly due to tachyonic preheating and parametric resonance, leading to efficient reheating.

Contribution

It offers the first detailed combined analytical and numerical study of nonperturbative preheating effects in new inflation scenarios.

Findings

Inflaton decay occurs in about 5 oscillations at GUT scale.

Decay is driven by tachyonic preheating and parametric resonance.

Reheating temperature is typically low.

Abstract

During the last ten years a detailed investigation of preheating was performed for chaotic inflation and for hybrid inflation. However, nonperturbative effects during reheating in the new inflation scenario remained practically unexplored. We do a full analysis of preheating in new inflation, using a combination of analytical and numerical methods. We find that the decay of the homogeneous component of the inflaton field and the resulting process of spontaneous symmetry breaking in the simplest models of new inflation usually occurs almost instantly: for the new inflation on the GUT scale it takes only about 5 oscillations of the field distribution. The decay of the homogeneous inflaton field is so efficient because of a combined effect of tachyonic preheating and parametric resonance. At that stage, the homogeneous oscillating inflaton field decays into a collection of waves of the inflaton field, with a typical wavelength of the order of the inverse inflaton mass. This stage usually is followed by a long stage of decay of the inflaton field into other particles, which can be described by the perturbative approach to reheating after inflation. The resulting reheating temperature typically is rather low.