Response Properties Of Strong Coupling Quark-Gluon Plasma

The confinement in Quantum Chromodynamics(QCD) leads to the bound state of quarks in hadrons, and deconfinement is difficult to achieve by dynamic methods. Therefore, one can only get high temperature environment by the relativistic heavy ion collision experiment to make quarks free under deconfinement phase transition, thus quarks can move freely in a relatively large range. However, the Quark-Gluon Plasma(QGP) signals from the relativistic heavy ion collision experiment show that the QGP produced in this experiment is strongly coupled. In this paper, we will study the response properties of strong coupling QGP with AdS/CFT correspondence.First, we briefly review the formalism of dielectric function, which reflects the essential difference between medium and vacuum, in the linear theory frame. And then we apply AdS/CFT correspondence to obtain the strong coupling polarization tensors in R-photon model.For static conditions, we discuss the static dielectric function and interaction potential in strong coupling by the strong coupling polarization tensors, and compare them with the weak coupling ones. We find that, the dielectric function in strong coupling is suppressed compared with that in weak coupling, and the interaction potential then presents a weaker screening characteristics in strong coupling, which indicates a smaller Debye mass compared with weak coupling.For non-static conditions, we discuss the wake potential induced by a fast moving charge in plasma and compare the strong coupling wake potentials with the weak coupling ones for different particle velocities. The comparison suggests, the most prominent difference between strong and weak coupling wake potential is that when v=0.99 c the remarkable oscillation due to Cerenkov-like radiation and Mach cone in weak coupling disappears in strong coupling, which implies that the plasmon mode with phase velocity lower than the speed of light does not exist in strong coupling plasma.