NONEQUILIBRIUM AUTOCORRELATIONS IN PHASE-ORDERING DYNAMICS

We investigate the ordering process of an unstable system governed by a nonconserved scalar order parameter using a theoretical approach developed previously. The two-time order-parameter correlation function is shown to obey asymptotic dynamical scaling. The temporal evolution of the autocorrelation function exhibits power-law decay with a nonequilibrium exponent. We find a relation between this exponent and a nonlinear eigenvalue controlling the equal-time structure factor. This relation, as well as the predicted values of the exponent, is compared with direct numerical simulations of a cell-dynamical-system (CDS) model of the ordering process.