Time-Evolution of Collective Meson Fields and Amplification of Quantum   Meson Modes in Chiral Phase Transition
  The time evolution of quantum meson fields in the O(4) linear sigma model is investigated in a context of the dynamical chiral phase transition. It is shown that amplitudes of quantum pion modes are amplified due to both mechanisms of a parametric resonance and a resonance by the forced oscillation according to the small oscillation of the chiral condensate in the late time of chiral phase transition. 
Y.Tsue (Kochi Univ., Japan)