Multi-Throat Brane Inflation

TL;DR

The paper introduces a multi-throat brane inflation scenario in which inflation is triggered by D3-branes slowly exiting a deeply warped IR throat, with energy density sourced by anti-D3-branes in other throats. Inflation does not rely on slow-roll flatness; instead, the warping and DBI-like dynamics drive the expansion, potentially accommodating a Randall-Sundrum hierarchy. The model yields a red-tilted density perturbation spectrum with small running and discusses reheating via inter-throat brane interactions, while highlighting subtle stringy effects and backreaction that warrant further study. Overall, it broadens the landscape of string-theoretic inflation by leveraging multi-throat warping and brane-flux dynamics to generate inflation and its observable signatures.

Abstract

We present a scenario where brane inflation arises more generically. We start with D3 and anti-D3-branes at the infrared ends of two different throats. This setup is a natural consequence of the assumption that in the beginning we have a multi-throat string compactification with many wandering anti-D3-branes. A long period of inflation is triggered when D3-branes slowly exit the highly warped infrared region, under a potential generically arising from the moduli stabilization. In this scenario, the usual slow-roll conditions are not required, and a large warping is allowed to incorporate the Randall-Sundrum model.