A study of dense matter in a AdS/QCD model

Y. Kim

Korea Institute for Advanced Study (KIAS),

with C.-H. Lee (PNU) and H. -U. Yee (KIAS)

Contents

• Brief review on hard wall model• Dense AdS/QCD• Summary

Let’s start from 2-flavor QCD andLet’s start from 2-flavor QCD andattempts to guess its 5D holographic dual,attempts to guess its 5D holographic dual,

AdS/CFT dictionaries.AdS/CFT dictionaries.

Bottom-up AdS/QCD model( look at QCD first !!! )

5D field contents

Operator --- 5D bulk field

[Operator] --- 5D mass

SU(2)LXSU(2)R gauge symmetry in AdS5

Current conservation --- gauge symmetry

5D Symmetry

Background: AdS5

Confinement

Confinement --- IR cutoff in z direction

Spontaneous chiral symmetry breaking

Hard wall model

Example: 4D vector meson mass

Dense AdS/QCD

For example,

In bottom-up approach,

So, the isospin or strange chemical potentialswill show up in the model, but not the baryon chemical potential.

At least in bottom-up with no explicit baryons, AdS/CFT may not help us with introducingthe baryon chemical potential into the game.Exception may be a anomaly related term.

Hard wall model with baryons

Mean field approach:

1. Chiral condensate

2. In-medium nucleon mass

3. Vector meson mass splitting in asymmetric matter

Note that AdS/CFT is not be able to fix the relation betweenthe chemical potential and its conjugate density.

Summary• With no explicit baryon fields, not much thing ma

y be done in bottom-up AdS/QCD at finite density, especially in the hard wall model.

• We turn on the baryon density in MFA.• Chiral condesate and nucleon mass decrease wit

h density.• We observe a mass splitting in the chared vector

mesons. • With omega-meson, we could introduce the baryo

n chemical potential without MFA (work in progress).