On complex Langevin dynamics and zeroes of the measure I: Formal proof   and simple models
  In the complex Langevin approach to lattice simulations at nonzero density, zeroes of the fermion determinant lead to a meromorphic drift and hence a need to revisit the theoretical derivation. We discuss how poles in the drift affect the formal justification of the approach and then explore the various potential issues in simple models, in a manner that is applicable to heavy dense and full QCD. 
Gert Aarts, Erhard Seiler, Denes Sexty, Ion-Olimpiu Stamatescu
hep-lat