Warped Deformed Throats have Faster (Electroweak) Phase Transitions

TL;DR

The paper analyzes finite-temperature phase transitions in warped Randall-Sundrum–like throats modeled on Klebanov-Tseytlin geometry, showing that the bubble action exhibits a mild $N^2$ dependence and is not exponentially enhanced by large degrees of freedom. Using a 5D EFT with gravity and a stabilizing scalar, it compares a warped broken phase to a high-temperature black hole phase, derives the critical temperature $T_c$ and the bubble-nucleation action $S_3/T$, and demonstrates that the transition can complete across a wider parameter range than in Goldberger-Wise stabilized RS models. A key result is that the IR-bound on the holographic degrees of freedom is the only hard constraint for completion, while the UV region preserves a reliable gravitational description even when the IR sector is strongly coupled. The findings have implications for electroweak symmetry breaking in Higgsless/string-inspired setups and for early-universe cosmology, where faster phase transitions can influence gravitational wave signals and thermal histories.

Abstract

We study the dynamics of the finite-temperature phase transition for warped Randall-Sundrum(RS)-like throat models related to the Klebanov-Tseytlin solution. We find that, for infrared branes stabilized near the tip of the throat, the bounce action has a mild N^2 dependence, where N(y) \sim [M_5 L(y)]^{3/2} is the effective number of degrees of freedom of the holographic dual QFT, and where L(y) is the local curvature radius, which decreases in the infrared. In addition, the bounce action is not enhanced by large numbers. These features allow the transition to successfully complete over a wider parameter range than for Goldberger-Wise stabilized RS models. Due to the increase of L(y) in the ultraviolet, the throat has a reliable gravitational description even when the number of infrared degrees of freedom is small. We also comment on aspects of the thermal phase transition in Higgsless models, where the gauge symmetry breaking is achieved via boundary conditions. Such models include orbifold-GUT models and the Higgsless electroweak symmetry breaking theories of Csaki et al., with Standard Model gauge fields living in the bulk.