Warped reheating in brane–antibrane inflation

We examine how reheating occurs after brane–antibrane inflation in warped geometries, such as those which have recently been considered for type IIB string vacua. We adopt the standard picture that the energy released by brane annihilation is dominantly dumped into massive bulk (closed-string) modes which eventually cascade down into massless particles, but argue that this need not mean that the result is mostly gravitons with negligible visible radiation on the Standard Model brane. Rather, in geometries having strongly warped throats we argue that this energy can instead be predominantly dumped into massless modes which are localized at the throat’s tip, because of the exponential growth of the massive Kaluza–Klein wavefunctions there. The result is preferentially to reheat those branes which lay in the most strongly warped throats. We argue that the efficiency of this process removes a conceptual obstacle to the construction of multi-throat models, wherein inflation occurs in a different throat to the one in which the Standard Model brane resides. Such multi-throat models are desirable because they may resolve a difficulty in reconciling inflation with the supersymmetry-breaking scale on the Standard Model brane, and because they may allow cosmic strings to be sufficiently long-lived to be observable during the present epoch.