Photoemission with chemical potential from QCD gravity dual

We consider a D4-D8-(D) over bar8 brane construction which gives rise to a large N QCD at sufficiently small energies. Using the gravity dual of this system, we study chiral phase transition at finite chemical potential and temperature and find a line of first order phase transitions in the phase plane. We compute the spectral function and the photon emission rate. The trace of the spectral function is monotonic at vanishing chemical potential, but develops some interesting features as the value of the chemical potential is increased. (c) 2007 Elsevier B.V. All rights reserved.