QCD simulations at small chemical potential
  Within the reweighting approach, one has the freedom to choose the Monte Carlo action so that it provides a good overlap with the finite-\mu measure but remains simple to simulate. We explore several choices of action in the regime of small \mu. Simulating with a finite isospin chemical potential \mu_I=\mu gives a better overlap than the standard choice \mu=0, with no computational overhead. 
Ph. de Forcrand, S. Kim, T. Takaishi