Shear viscosity and phase diagram from Polyakov-Nambu-Jona-Lasinio model

We present a detailed study of the variation of shear viscosity eta, with temperature and baryon chemical potential within the framework of the Polyakov-Nambu-Jona-Lasinio model. eta is found to depend strongly on the spectral width of the quasiparticles present in the model. The variation of eta across the phase diagram has distinctive features for different kinds of transitions. These variations have been used to study the possible location of the critical end point and are cross-checked with similar studies of variations of specific heat. Finally, using a parametrization of the freeze-out surface in heavy-ion collision experiments, the variation of the shear viscosity to entropy density ratio has also been discussed as a function of the center-of- mass energy of collisions.