Generic sandpile models have directed percolation exponents.
We study sandpile models with stochastic toppling rules and having sticky grains so that with a nonzero probability no toppling occurs, even if the local height of pile exceeds the threshold value. Dissipation is introduced by adding a small probability of particle loss at each toppling. Generically for the models with a preferred direction, the avalanche exponents are those of critical directed percolation clusters. For undirected models, avalanche exponents are those of directed percolation clusters in one higher dimension.
Mohanty
P K
PK
Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai-400 005, India.
Dhar
Deepak
D