Conservation laws, anisotropy, and self-organized criticality in noisy nonequilibrium systems

It is argued in the context of noisy, nonequilibrium Langevin models that systems with conserving deterministic dynamics and noise which violates the conservation law always exhibit self-organized criticality spatial and temporal correlations that decay algebraically under generic conditions. Systems with both conserving deterministic dynamics and conserving noise require spatial anisotropy to exhibit self-organized criticality. © 1990 The American Physical Society.