Holographic Spectral Functions at Finite Baryon Density

TL;DR

This paper uses holography to compute spectral functions of thermal super Yang Mills with finite baryon density, revealing how baryon charge influences spectral properties and photon production.

Contribution

It provides the first detailed holographic analysis of spectral functions at finite baryon density, including coupled vector and scalar channels and photon production effects.

Findings

Spectral functions are computed at finite baryon density.

Baryon charge affects photon production rates.

Conductivity results match previous macroscopic calculations.

Abstract

Using the AdS/CFT correspondence, we compute the spectral functions of thermal super Yang Mills at large N_c coupled to a small number of flavours of fundamental matter, N_f<<N_c, in the presence of a nonzero baryon density. The holographic dual of such a theory involves the addition of probe D7-branes with a background worldvolume gauge field switched on, embedded in the geometry of a stack of black D3-branes. We perform the analysis in the vector and scalar channels which become coupled for nonzero values of the spatial momentum and baryon density. In addition, we obtain the effect of the presence of net baryon charge on the photon production. We also extract the conductivity and find perfect agreement with the results derived by Karch and O'Bannon in a macroscopic setup.