Heavy quark free energies and screening at finite temperature and   density
  We study the free energies of heavy quarks calculated from Polyakov loop correlation functions in full 2-flavour QCD using the p4-improved staggered fermion action. A small but finite Baryon number density is included via Taylor expansion of the fermion determinant in the Baryo-chemical potential mu. For temperatures above Tc we extract Debye screening masses from the large distance behaviour of the free energies and compare their mu-dependence to perturbative results. 
M. Doring, S. Ejiri, O. Kaczmarek, F. Karsch, E. Laermann