ORDERING KINETICS IN SYSTEMS WITH LONG-RANGE INTERACTIONS

The growth kinetics following a quench from high temperatures to zero temperature is studied using the time-dependent Ginzburg-Landau model. We investigate d-dimensional systems with n-component order parameter and assume that the interactions decay with distance r as V(r) is sim ilar to r(-d-sigma) with 0 < sigma < 2. The spherical limit (n = infin ity) is solved for both conserved and nonconserved order-parameter dyn amics and the scaling properties of the structure factor are calculate d. We find scaling features (including multiscaling in the conserved c ase) that are similar to those of systems with short-range interaction s. The essential difference is that the short-range value of the dynam ic critical exponent z(s) is replaced by z = z(s) - 2 + sigma and the form of the scaling function is modified. We also study the general n case for non-conserved order-parameter dynamics and calculate the stru cture factor in an approximate scheme with the results that (i) the sp herical-limit value of z remains unchanged as n is decreased down to n = 1 and (ii) the spatial correlations decay at large distances as r(- d-sigma).