Holographic QCD phase diagram with critical point from Einstein–Maxwell-dilaton dynamics

Abstract

Supplementing the holographic Einstein–Maxwell-dilaton model of [1,2] by input of lattice QCD data for 2+1 flavors and physical quark masses for the equation of state and quark number susceptibility at zero baryo-chemical potential we explore the resulting phase diagram over the temperature-chemical potential plane. A first-order phase transition sets in at a temperature of about 112 MeV and a baryo-chemical potential of 612 MeV. We estimate the accuracy of the critical point position in the order of approximately 5–8% by considering parameter variations and different low-temperature asymptotics for the second-order quark number susceptibility. The critical pressure as a function of the temperature has a positive slope, i.e. the entropy per baryon jumps up when crossing the phase border line from larger values of temperature/baryo-chemical potential, thus classifying the phase transition as a gas–liquid one. The updated holographic model exhibits in- and outgoing isentropes in the vicinity of the first-order phase transition.