Pseudofermion observables for static heavy meson decay constants on the   lattice
  A method based on the Monte Carlo inversion of the Dirac operator on the lattice provides low noise results for the correlations entering the definition of the heavy meson decay constant in the static limit. The method is complementary to the usual method of smeared sources, avoids the systematic error arising from optimizing the size of the smearing volume and is more efficient for the values of lattice parameters that we have explored. 
G.M.de Divitiis, R. Frezzotti, M. Masetti, R. Petronzio