Approach to Scaling in Phase-Ordering Kinetics

The influence of the initial fluctuations on the onset of scaling in the quench to zero temperature of a two dimensional system with conserved order parameter is analyzed in detail with and without topological defects. We find that the initial fluctuations greatly affect the way scaling is reached, while the number of components of the order parameter does not play a significant role. Under strong initial fluctuations the preasymptotic linear behavior is replaced by the mean field behavior of the large- $N$ model, producing the multiscaling to standard-scaling crossover also in the physically interesting cases of systems with a small number of components.