Sign problem and MEM
  The sign problem is notorious in Monte   Carlo simulations of lattice QCD with the finite density, lattice field theory (LFT) with a $\theta$ term and quantum spin models. In this report, to deal with the sign problem, we apply the maximum entropy method (MEM) to LFT with the $\theta$ term and investigate to what extent the   MEM is applicable to this issue. Based on this study, we also make a brief comment about lattice QCD with the finite density in terms of the   MEM. 
Masahiro Imachi, Yasuhiko Shinno and Hiroshi Yoneyama