QUANTUM EVOLUTION OF DISORIENTED CHIRAL CONDENSATES

The nonequilibrium evolution of the hadronic plasma produced in a high energy heavy ion collision is studied in the O(4) linear σ model to leading order in a large N expansion. Starting from an approximate equilibrium configuration at an initial proper time τ in the disordered phase we study the transition to the ordered broken symmetry phase as the system expands and cools. We give results for the proper time evolution of the effective pion mass, the order parameter σ as well as for the pion two point correlation function. We study the phase space of initial conditions that lead to instabilities (exponentially growing long wavelength modes) which can lead to disoriented chiral condensates. We find that as a consequence of the strong self-coupling instabilities can exist for proper times that are at most 3 fm/c and lead to condensate regions that do not contain large number of particles. © 1995 The American Physical Society.