QCD Phase Transition In Gauge/gravity Duality

Quantum chromodynamics(QCD)phase transition is a important topic in high energy nuclear physics.Since 1997,the well-known Anti-de Sitter/Conformal Field Theory cor-respondence(AdS/CFT)proposed by Maldacena has been widely used in many fields and become one of powerful tools for tackling strong coupling problems.Since QCD phase transition is considered to be strongly coupled,the perturbation method become invalid.Using a five-dimension gravitational model to describe four-dimension gauge theory can be called as gauge/gravity duality or holographic QCD.We use gauge/gravity duality to study the QCD phase transition problems in this paper.First,we calculate the temperature and order of chiral phase diagram in T-? plane through the quark-antiquark pair condensate and realize the critical end point(CEP)in T-? plane by using a improved Einstein-Maxwell-Dilaton(EMD)gravitational model.We also calculate the temperature and order of deconfinement phase transition in T-? plane through the order parameter Polyakov loop.We find the temperature of deconfinement phase transition has a weak dependence on the chemical potential and realize the quarkonic phase in holographic QCD,which is qualitatively consistent with Polyakov-Nambu-Jona-Lasinio(PNJL)model.Further,we study the thermodynamic properties of strongly coupled matter around the CEP in EMD model and find the critical exponents(??0,??0.54,??1.04,??2.97)are consistent with mean-field approximation.We also discuss the possibilities to go beyond the mean field approximation.Moreover,we extend the EMD model to rotating case and calculate the effect of ro-tation on equation of state(EoS)and deconfinement phase transition since the QCD matter created in relativistic heavy ion collisions carries the angular momentum in the range of 103h-105h.We find the effect of rotation which is similar to chemical petantial will suppress the phase transition temperature.Lastly,we introduce a constant magnetic field in the EMD model since a strong magnetic field created in relativistic heavy ion collisions will reach 0.1?0.5GeV and nu-merically calculate the effect of magnetic field and chemical potential on QCD running coupling.We find magnetic field and chemical potential will suppress the QCD running coupling at fixed temperature and inter-quark distance.It may provide some insights into deconfinement phase transition.