Holographic Description of the QCD Phase Diagram And Out of Equilibrium Dynamics

Nick Evans

doi:10.1051/epjconf/20147000041

Abstract

Holography provides a powerful tool to model QCD and other strongly coupled gauge dynamics. As examples of its power to compute in novel environments I review some recent results: these include models of the phase structure of QCD at finite temperature and chemical potential; and computation of time dependent processes at strongly coupled phase transitions.

Highlights

This talk is intended as a small advert for using holography [1, 2] to study strongly coupled systems such as QCD
The main conclusion is that reducing the strength of the conformal symmetry breaking in the gauge coupling leads to a preference for a first order chiral phase transition
The second order transition at low density in the figure on the right is the main result. This sensibly motivated phenomenological tinkering suggests that the phase structure of strongly coupled gauge theories is quite sensitive to the precise conformal symmetry breaking structure, but that it is possible to model a range of phase diagrams using holography

Summary

Introduction

This talk is intended as a small advert for using holography [1, 2] to study strongly coupled systems such as QCD. The most clear cut example of this formalism is for the conformal N = 4 supersymmetric gauge theory with a large number of colours (the theory has a gauge field, 6 real scalars and 4 two-component gauginos all in the adjoint representation of SU(N)). In string theory this theory lives on the worldvolume of a stack of D3 branes in the limit where the string tension is taken to infinity. We compute at finite density and look at time dependent problems to show the technique’s versatility

Quarks

Chiral Symmetry Breaking and Confinement

Temperature and Density

Phase Diagrams

Out of Equilibrium Dynamics

Conclusions