Morphology of early stage phase ordering

We present results of Monte Carlo simulations of critical quenches in Ising models with long range interactions indicating that linear theories of continuous ordering such as Cahn-Hilliard-Cook theory break down first at high wave numbers or small length scales. We connect this breakdown to the formation of isolated domains that resemble the stable phases. These domains grow and coalesce, causing deviations from the linear theory to appear at smaller wave numbers. When the domains of up (down) spins percolate the failure of the linear theory occurs on all length scales and the system has chosen the up (down) global magnetization state.