Les Houches Lectures on Warped Models and Holography
Tony Gherghetta
TL;DR
The paper presents warped extra dimensions as a compelling framework to address the electroweak hierarchy problem, leveraging the RS1 geometry and its AdS/CFT dual to reinterpret the hierarchy in terms of a low IR cutoff and a strongly coupled 4D CFT. It develops a full 5D–4D dictionary to localize zero modes in the warped bulk, realize the Standard Model in the bulk, and interpret Higgs and fermion sectors as predominantly elementary or composite states depending on localization. The lectures cover how a pseudo-Nambu-Goldstone Higgs or supersymmetric mechanisms can yield a light Higgs while remaining radiatively stable, and discuss grand unification with logarithmic running in warped space, including partly supersymmetric realizations. The framework yields predictive phenomenology, with testable implications at colliders and a powerful holographic lens on strongly coupled gauge dynamics, offering a complete, calculable alternative to conventional 4D approaches. Overall, warped models unify hierarchy resolution, flavor structure, and unification in a single geometric and holographic scaffold, with concrete paths toward experimental validation.
Abstract
The theoretical tools required to construct models in warped extra dimensions are presented. This includes how to localise zero modes in the warped bulk and how to obtain the holographic interpretation using the AdS/CFT correspondence. Several models formulated in warped space are then discussed including nonsupersymmetric and supersymmetric theories as well as their dual interpretation. Finally it is shown how grand unification occurs in warped models.