The Medium Effects Of Dissipative Quark-gluon Plasma

Quark is the smallest unit of matter under the standard model of particle physics.Through the extreme relativistic heavy ion collisions,a high temperature and large density environment is formed,which the hadron vacuum structure is destroyed and produces a special state of matter: Quark-gluon plasma(QGP).The relativistic heavy ion collider(RHIC)at Brookhaven National Laboratory(BNL)and the Large Hadron Collider(LHC)at CERN have provided powerful evidence for QGP formation.Jet quenching at large momentum is an important discovery in RHIC,which has been considered as the characteristic signal of QGP formation.The collective flow at small momentum indicates that the generated QGP behaves like perfect fluid with a small shear viscosity.The polarization and fluctuation chromoelectromagnetic fields will be produced at the same time when a fast quark travels through QGP,these fields exerting in return on the quark will cause energy loss to it.Collisions are the important sources of dissipation,comparing to the polarization energy loss,the fluctuation energy loss is also important at a specific momentum.One of the purposes in this paper is to derive the dielectric functions from the dynamical equations associating with the BGK collision terms,collision rate is embedded in the expression of dielectric functions,which determines the fluctuation energy of quark when it travel through QGP.Based on the dielectric functions,we will discuss the effect of collision on fluctuation energy,numerical results indicate that compared to the collisionless case,the collision remarkably augments the fluctuation energy gain.At the initial state of off-central collision,the very strong electromagnetic field will be generated in the medium.The electric conductivity is not only an important aspect of the medium's electromagnetic properties,but also a parameter to characterize the charge transport in the system.It is significant that the interference between shear viscosity and electric conductivity to the evolution of QCD matter.Under the theoretical framework of dissipative relativistic hydromechanics,we willcalculate the electric conductivity of QGP medium and study the effect of shear viscosity to electric conductivity,the results of study indicate that shear viscosity will affect the transport process of charge in the medium.