Energy Transfer between Throats from a 10d Perspective

TL;DR

This paper calculates energy transfer rates between warped regions (throats) in string theory compactifications using a 10d approach, revealing suppression effects related to the size of the compact space and throat separation.

Contribution

It provides a 10d calculation of energy transfer rates between throats, extending previous 5d models and highlighting the impact of the compact space size and throat distance.

Findings

Energy transfer rates are suppressed when the Calabi-Yau size exceeds AdS scales.

Small throat separation can partially offset the suppression.

Results are relevant for reheating after brane inflation.

Abstract

Strongly warped regions, also known as throats, are a common feature of the type IIB string theory landscape. If one of the throats is heated during cosmological evolution, the energy is subsequently transferred to other throats or to massless fields in the unwarped bulk of the Calabi-Yau orientifold. This energy transfer proceeds either by Hawking radiation from the black hole horizon in the heated throat or, at later times, by the decay of throat-localized Kaluza-Klein states. In both cases, we calculate in a 10d setup the energy transfer rate (respectively decay rate) as a function of the AdS scales of the throats and of their relative distance. Compared to existing results based on 5d models, we find a significant suppression of the energy transfer rates if the size of the embedding Calabi-Yau orientifold is much larger than the AdS radii of the throats. This effect can be partially compensated by a small distance between the throats. These results are relevant, e.g., for the analysis of reheating after brane inflation. Our calculation employs the dual gauge theory picture in which each throat is described by a strongly coupled 4d gauge theory, the degrees of freedom of which are localized at a certain position in the compact space.