The Subtleties of the Wigner Function Formulation of the Chiral Magnetic   Effect
  We assess the applicability of the Wigner function formulation in its present form to the chiral Magnetic Effect and noted some issues regarding the conservation and the consistency of the electric current in the presence of an inhomogeneous and time dependent axial chemical potential. The problems are rooted in the ultraviolet divergence of the underlying field theory associated with the axial anomaly and can be fixed with the Pauli-Villars regularization of the Wigner function. 
Yan Wu, Defu Hou, and Hai-cang Ren
hep-ph hep-th nucl-th