New proposal for numerical simulations of systems with a theta-vacuum   term
  A new approach to perform numerical simulations of systems with a theta-vacuum term is proposed, tested, and applied to CP3 The main new ingredient of this approach is the method used to compute the probability distribution function of the topological charge at theta=0. We comment also on the possibility of applying this approach to QCD at finite baryon density. 
Vicente Azcoiti, Giuseppe Di Carlo, Angelo Galante, Victor Laliena