Chasing brane inflation in string theory

Abstract

We investigate the embedding of brane–antibrane inflation into a concretetype IIB string theory compactification with all moduli fixed. Specifically,we are considering a D3-brane, whose position represents the inflatonϕ, in a warped conifold throat in the presence of supersymmetrically embedded D7-branesand an anti-D3-brane localized at the tip of the warped conifold cone. After presenting themoduli stabilization analysis for a general D7-brane embedding, we concentrate on twoexplicit models, the Ouyang and the Kuperstein embeddings. We analyze whether theforces induced by moduli stabilization and acting on the D3-brane might be canceled byfine-tuning so as to leave us with the original Coulomb attraction of the anti-D3-braneas the driving force for inflation. For a large class of D7-brane embeddings weobtain a negative result. Cancelations are possible only for very small intervals ofϕ around an inflection point and not globally. For the most part of its motion the inflatonthen feels a steep, non-slow-roll potential. We study the inflationary dynamics induced bythis potential.