Holography of Strongly Coupled Gauge Theories

TL;DR

This paper reviews the development of holographic models for strongly coupled gauge theories, including applications to QCD and composite Higgs models, highlighting methods and open questions about energy scale separation.

Contribution

It introduces a refined holographic approach to model various gauge theories, including quark representations and higher operators, and discusses implications for confinement and chiral symmetry breaking.

Findings

Holographic models can describe spectra of different gauge theories.

A 'perfected' AdS dual for QCD is presented.

Questions raised about energy scale separation and symmetry breaking.

Abstract

The "periodic table" of strongly coupled gauge theories remains only sketchily understood. Holography has developed to the point where bottom up constructions can describe the spectrum of individual gauge theories (based on assumptions of their running) including quarks in different representations and higher dimension operators. I highlight the method with a "perfected" version of an AdS dual of QCD and results for composite higgs models with two representations of quarks. The method raises questions about the degree to which energy scales can be split in generic gauge theories including whether confinement and chiral symmetry breaking are linked.