Probing deconfinement in a chiral effective model with Polyakov loop at imaginary chemical potential

Abstract

The phase structure of the two-flavor Polyakov-loop extended Nambu-Jona-Lashinio model is explored at finite temperature and imaginary chemical potential with a particular emphasis on the confinement-deconfinement transition. We point out that the confined phase is characterized by a cos3μI/T dependence of the chiral condensate on the imaginary chemical potential while in the deconfined phase this dependence is given by cosμI/T and accompanied by a cusp structure induced by the Z(3) transition. We demonstrate that the phase structure of the model strongly depends on the choice of the Polyakov loop potential U. Furthermore, we find that by changing the four fermion coupling constant Gs, the location of the critical end point of the deconfinement transition can be moved into the real chemical potential region. We propose a new parameter characterizing the confinement-deconfinement transition.