Nonequilibrium phase ordering with a global conservation law.

In all dimensions, infinite-range Kawasaki spin exchange in a quenched Ising model leads to an asymptotic length scale L\ensuremath{\sim}(\ensuremath{\rho}t${)}^{1/2}$\ensuremath{\sim}${\mathit{t}}^{1/3}$ at T=0 because the kinetic coefficient is renormalized by the broken-bond density, \ensuremath{\rho}\ensuremath{\sim}${\mathit{L}}^{\mathrm{\ensuremath{-}}1}$. For T\ensuremath{\gtrsim}0, activated kinetics recovers the standard asymptotic growth law, L\ensuremath{\sim}${\mathit{t}}^{1/2}$. However, at all temperatures, infinite-range energy transport is allowed by the spin-exchange dynamics. A better implementation of global conservation, the microcanonical Creutz algorithm, is well behaved and exhibits the standard nonconserved growth law, L\ensuremath{\sim}${\mathit{t}}^{1/2}$, at all temperatures. \textcopyright{} 1996 The American Physical Society.