Rare events and breakdown of simple scaling in the Abelian sandpile model

Due to intermittency and conservation, the Abelian sandpile in two dimensions obeys multifractal, rather than finite size scaling. In the thermodynamic limit, a vanishingly small fraction of large avalanches dominates the statistics and a constant gap scaling is recovered in higher moments of the toppling distribution. Thus, rare events shape most of the scaling pattern and preserve a meaning for effective exponents, which can be determined on the basis of numerical and exact results. © 1998 The American Physical Society.