Holographic Methods and Gauge-Higgs Unification in Flat Extra Dimensions

TL;DR

The article develops and applies holographic techniques to study Gauge-Higgs Unification in a single flat extra dimension and demonstrates how the Higgs potential and Yukawa couplings can be computed efficiently via boundary data. It shows that the Higgs potential is radiatively generated and finite due to the Wilson-line nature of the Higgs, enabling realistic EWSB when additional model-building ingredients are included. Two realistic flat-space GHU models are presented: an $SU(3)$-based model with Lorentz breaking and a mirror symmetry, and an $SO(5)$-based model with large localized gauge kinetic terms that harness custodial protection; both yield TeV-scale compactification and testable predictions, such as Kaluza-Klein resonances, while keeping oblique and flavor-like constraints under control. The work connects flat-space GHU to analogous warped-space constructions, highlighting how holography aids in handling nontrivial boundary effects and Yukawa generation, and discusses higher-dimensional extensions and their challenges.

Abstract

I review the holographic techniques used to efficiently study models with Gauge-Higgs Unification (GHU) in one extra dimension. The general features of GHU models in flat extra dimensions are then reviewed, emphasizing the aspects related to electroweak symmetry breaking. Two potentially realistic models, based on SU(3) and SO(5) electroweak gauge groups, respectively, are constructed.