Role of mesonic fluctuations in the Polyakov loop extended quark-meson   model at imaginary chemical potential
  We explore the thermodynamics and phase structure of the Polyakov loop-extended two flavor chiral quark--meson (PQM) model beyond the mean-field approximation at imaginary chemical potential. Our approach is based on the functional renormalization group (FRG) method. At finite temperature and imaginary chemical potential, we solve the renormalization group flow equation for a scale-dependent thermodynamic potential in the presence of the gluonic background field. We determine behavior of order parameters of the PQM model in the FRG approach and compute the phase diagram. We compare our FRG results with that obtained in the mean-field approximation at imaginary chemical potential. 
Kenji Morita, Vladimir Skokov, Bengt Friman, Krzysztof Redlich
hep-ph hep-lat nucl-th