Chiral phase transition and QCD phase diagram from AdS/QCD

We study the chemical potential effects on the chiral phase transition in a simply improved soft-wall AdS/QCD model, which can realize consistently the properties of linear confinement and spontaneous chiral symmetry breaking. The mu - T phase diagrams with both zero and physical quark masses have been obtained from this model. For the case of physical quark mass, the chiral transition has a crossover behavior at low chemical potential. With the increase of the chemical potential mu, the critical temperature T-c descends toward zero, and the crossover transition turns into a first-order one at some intermediate value of mu, which implies that a critical endpoint naturally exists in this improved soft-wall model. All these features agree with our current perspective on the quantum chromodynamics phase diagram.