Worm algorithms for the 3-state Potts model with magnetic field and   chemical potential
  We discuss worm algorithms for the 3-state Potts model with external field and chemical potential. The complex phase problem of this system can be overcome by using a flux representation where the new degrees of freedom are dimer and monomer variables. Working with this representation we discuss two different generalizations of the conventional Prokof'ev-Svistunov algorithm suitable for Monte Carlo simulations of the model at arbitrary chemical potential and evaluate their performance. 
Ydalia Delgado, Hans Gerd Evertz, Christof Gattringer
hep-lat cond-mat.other