Large scale structures, symmetry, and universality in sandpiles.
We introduce a sandpile model where, at each unstable site, all grains are transferred randomly to downstream neighbors. The model is local and conservative, but not Abelian. This does not appear to change the universality class for the avalanches in the self-organized critical state. It does, however, introduce long-range spatial correlations within the metastable states. For the transverse direction d(perpendicular)>0, we find a fractal network of occupied sites, whose density vanishes as a power law with distance into the sandpile.
Hughes
David
D
Department of Mathematics, Imperial College of Science, Technology and Medicine, London SW7 2BZ, United Kingdom.
Paczuski
Maya
M