Geometric Quantization of free fields in space of motions
  Via K$\ddot{a}$hker polarization we geometrically quantize free fields in the spaces of motions, namely the space of solutions of equations of motion. We obtain the correct results just as that given by the canonical quantization. Since we follow the method of covariant symplectic current proposed by Crnkovic, Witten and Zuckerman et al, the canonical commutator we obtained are naturally invariant under proper Lorentz transformation and the discrete parity and time transverse transformations, as well as the equations of motion. 
M.X Shao, Z.Y Zhu (ITP, P.R.China)