On the Sign Problem of the Fermionic Shadow Wave Function
  We present a whole series of novel methods to alleviate the sign problem of the Fermionic Shadow Wave Function in the context of Variational Monte Carlo. The effectiveness of our new techniques is demonstrated on the example of liquid 3He. We found that although the variance is substantially reduced, the gain in efficiency is restricted by the increased computational cost. Yet, this development not only extends the scope of the Fermionic Shadow Wave Function, but also facilitates highly accurate Quantum Monte Carlo simulations previously thought not feasible. 
Francesco Calcavecchia and Francesco Pederiva and Malvin H. Kalos and   Thomas D. K\"uhne
physics.comp-ph cond-mat.dis-nn cond-mat.stat-mech cond-mat.str-el quant-ph