On Tunnelling In Two-Throat Warped Reheating

TL;DR

This paper investigates energy transfer mechanisms in two-throat warped geometries, revealing that KK mode interactions can enhance energy transfer beyond tunnelling rates, with implications for reheating scenarios.

Contribution

It provides a detailed analysis of KK mode tunnelling and interactions in two-throat models, showing how modifications to the warp factor can enhance energy transfer rates.

Findings

KK mode wavefunctions overlap allows energy transfer beyond tunnelling.

Decay rates are faster than previously thought but are slowed by mode frequency imaginary parts.

Warp factor modifications can significantly enhance energy transfer rates.

Abstract

We revisit the energy transfer necessary for the warped reheating scenario in a two-throat geometry. We study KK mode wavefunctions of the full two-throat system in the Randall--Sundrum (RS) approximation and find an interesting subtlety in the calculation of the KK mode tunnelling rate. While wavepacket tunnelling is suppressed unless the Standard Model throat is very long, wavefunctions of modes localized in different throats have a non-zero overlap and energy can be transferred between the throats by interactions between such KK modes. The corresponding decay rates are calculated and found to be faster than the tunnelling rates found in previously published works. However, it turns out that the imaginary parts of the mode frequencies, induced by the decay, slow the decay rates themselves down. The self-consistent decay rate turns out to be given by the plane wave tunnelling rate considered previously in the literature. We then discuss mechanisms that may enhance the energy transfer between the throats over the RS rates. In particular, we study models in which the warp factor changes in the UV region less abruptly than in the RS model, and find that it is easy to build phenomenological models in which the plane wave tunnelling rate, and hence the KK mode interaction rates, are enhanced compared to the standard RS setup.