Bulk viscosity of hot dense Quark matter in PNJL model

Starting from the Kubo formula and the the QCD low energy theorem, we study the the bulk viscosity of hot dense quark matter in the PNJL model from the equation of state . We show that the bulk viscosity has a sharp peak near the chiral phase transition, and the ratio of bulk viscosity over entropy rises dramatically in the vicinity of the phase transition. These results agrees with that from lattice and other model calculations. In addition, we show that the increase of chemical potential raises the bulk viscosity.