FORMING DISORIENTED CHIRAL CONDENSATES THROUGH FLUCTUATIONS

Using the influence functional formalism, classical equations of motio n for the O(N) model are derived in the presence of a heat bath, in bo th the symmetric phase as well as the phase of spontaneously broken sy mmetry. The heat bath leads to dissipation and fluctuation terms in th e classical equations of motion, which are explicitly computed to lowe st order in perturbation theory. In the broken phase these terms are f ound to be large for the sigma field, even at zero temperature, due to the decay process sigma-->pi pi, while they are small for the pi fiel ds at temperatures below T(c)similar or equal to 160 MeV. It is shown that in large Volumes the presence of dissipation and fluctuations sup presses the formation of disoriented chiral condensates (DCC's). In sm all volumes, however, fluctuations become sufficiently large to induce the formation of DCC's even if chiral symmetry has not been restored in the initial stage of the system's evolution. [S0556-2813(98)02810-6 ].