摘要
The origin of power-law distributions in self-organized criticality is investigated by treating the variation of the number of active sites in the system as a stochastic process. An avalanche is mapped to a first-return random-walk process in a one-dimensional lattice. In order to understand the reason of variant exponents for the power-law distributions in different self-organized critical systems, we introduce the correlations among evolution steps. Power-law distributions of the lifetime and spatial size are found when the random walk is unbiased with equal probability to move in opposite directions. It is found that the longer the correlation length, the smaller values of the exponents for the power-law distributions.
基金
Supported in part by the National Natural Science Foundation of China under Grant Nos.10635020 and 10775057
by the Ministry of Education of China under Grant Nos.306022,IRT0624
by the Programme of Introducing Talents of Discipline to Universities under Grant No.B08033
