Holographic D instanton liquid and chiral transition

Abstract

We study the phase diagram of black D3 geometry with uniformly distributed D-instanton charge using the probe D7 brane. In the presence of uniform D-instanton charges, quarks can be confined, although gluons are not, because baryon vertices are allowed due to the net repulsive force on the on the probe D-branes. Since there is no scale in the geometry itself apart from the horizon size, there is no Hawking-Page transition. As a consequence, the D7 brane embedding can encode the effect of the finite temperature as well as finite baryon density even for low temperature. The probe D-brane embedding, however, undergoes a phase transition which can be interpreted as a chiral transition as we change temperature and density. We studied such phase transitions and calculated the constituent quark mass, chiral condensation, and the binding energy of baryons as function of the density. The baryon vertex melting is identified as the quark deconfinement. We draw the phase diagram according to these transitions.