nLab
't Hooft coupling

Contents

Context

Quantum Field Theory

algebraic quantum field theory (perturbative, on curved spacetimes, homotopical)

Introduction

Concepts

field theory:

Lagrangian field theory

quantization

quantum mechanical system, quantum probability

free field quantization

gauge theories

interacting field quantization

renormalization

Theorems

States and observables

Operator algebra

Local QFT

Perturbative QFT

Contents

Idea

In Yang-Mills theory/QCD with coupling constant g YMg_{YM} and with N cN_c colours, the ’t Hooft coupling is the expression

λg YM 2N c. \lambda \;\coloneqq\; g_{YM}^2 N_c \,.

Properties

In the large NN limit

The study of Yang-Mills theory in the large N limit but at fixed ’t Hooft coupling controls the AdS/CFT correspondence:

large N limitN cN_c \to \infty at fixed 't Hooft coupling λ=g YM 2N c\lambda = g_{YM}^2 N_c

λ<1\lambda \lt 1λ>1\lambda \gt 1
small coupling limit of Yang-Mills theorylow-energy supergravity limit of string theory on asymptotically AdS spacetime

(e. g. Aharony-Gubser-Maldacena-OoguriOz 99, p. 11, p. 60, Nastase 07, Section 8)

(…)

References

The original article

Review:

Last revised on January 22, 2020 at 10:32:10. See the history of this page for a list of all contributions to it.