Energy-scaling approach to phase-ordering growth laws.

We present a simple, unified approach to determining the growth law for the characteristic length scale L(t) in the phase ordering kinetics of a system quenched from a disordered phase to within an ordered phase. This approach, based on a scaling assumption for pair correlations, determines L(t) self-consistently for purely dissipative dynamics by computig the time dependence of the energy in two ways. We derive growth laws for conserved and nonconserved O(n) models, including two-dimensional XY models and systems with textures. We demonstrate that the growth laws for other systems, such as liquid crystals and Potts models, are determined by the type of topological defect in the order parameter field that dominates the energy. We also obtain generalized Porod laws for systems with topological textures.