STRUCTURE AND THE FAILURE OF THE LINEAR-THEORY OF CONTINUOUS ORDERING

We present the results of numerical investigations of Ising models und ergoing continuous ordering which indicate, for systems with large but finite interaction range R, that the time interval during which the l inear theory of Cahn, Hilliard, and Cook fits the simulation data depe nds strongly on the length scale of observation. We associate the init ial linear theory deviation at small length scales with the appearance of isolated structures or domains which form after a quench into the unstable region of thermodynamic space. These domains cannot be descri bed by a linear theory; this implies, in contrast to earlier results, that the linear theory ''breakdown'' cannot be obtained by investigati on of the linear itself for inconsistencies.