Dynamical Theory of Disoriented Chiral Condensates at QCD Phase Transition

We apply the canonical quantum field theory based on the Liouville-von Neumann equation to the nonequilibrium linear sigma model. Particular emphasis is put on the mechanism for domain growth of disoriented chiral condensates due to long wavelength modes and its scaling behavior. Scattering effects, decoherence and emergence of order parameter are also discussed beyond the Hartree approximation.