The Throat as a Randall-Sundrum Model with Goldberger-Wise Stabilization
Felix Bruemmer, Arthur Hebecker, Enrico Trincherini
TL;DR
The paper shows that flux-stabilized warped throats in type IIB string theory can be recast as a Randall-Sundrum–type 5d model with Goldberger-Wise stabilization. The bulk scalar H, microscopically tied to NS-NS B_2 flux on the S^2 in the throat, develops a nontrivial profile that backreacts on the geometry and fixes the throat length via boundary values, while the universal Kähler modulus acts as a UV-brane field controlling a large 4d curvature term. An explicit 5d action is constructed, combining bulk gravity with H, boundary potentials, and brane terms, to reproduce the key features of the 10d solution and radion stabilization. The work links 10d flux compactifications to a tractable 5d EFT, enabling phenomenological and cosmological applications and guiding future SUSY embeddings and a more complete reduction to 4d moduli dynamics.
Abstract
An interesting feature of type IIB flux compactifications is the natural presence of strongly warped regions or `throats'. These regions allow for a 5d Randall-Sundrum model interpretation with a large hierarchy between the UV and IR brane. We show that, in the 5d description, the flux stabilization of this hierarchy (or, equivalently, of the brane-to-brane distance) can be understood as an implementation of the Goldberger-Wise mechanism. This mechanism relies on the non-trivial bulk profile of the so-called Goldberger-Wise scalar, which in addition has fixed expectation values at the boundaries and thereby stabilizes the size of the 5d interval. The Goldberger-Wise scalar is realized microscopically by the continuously varying flux of the Neveu-Schwarz 2-form potential B_2 on the S^2 cycle in the throat. Its back-reaction on the 5d geometry leads to a significant departure from a pure AdS_5 background. We also find that, for a wide range of parameters, the universal Kaehler modulus of the 10d compactification plays the role of a UV-brane field in the equivalent 5d model. It governs the size of a large 4d curvature term localized at the UV brane. We hope that our simple 5d description of the stabilized throat will be useful in various phenomenological and cosmological applications and that refined versions of this construction will be able to account for all relevant details of the 10d model.