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Full-Text Articles in Physics
Universality In Sandpiles, A Chessa, H E. Stanley, A Vespignani, S Zapperi
Universality In Sandpiles, A Chessa, H E. Stanley, A Vespignani, S Zapperi
Alessandro Vespignani
We perform extensive numerical simulations of different versions of the sandpile model. We find that previous claims about universality classes are unfounded, since the method previously employed to analyze the data suffered from a systematic bias. We identify the correct scaling behavior and provide evidences suggesting that sandpiles with stochastic and deterministic toppling rules belong to the same universality class.
Critical Behavior And Conservation In Directed Sandpiles, R Pastor-Satorras, A Vespignani
Critical Behavior And Conservation In Directed Sandpiles, R Pastor-Satorras, A Vespignani
Alessandro Vespignani
We perform large-scale simulations of directed sandpile models with both deterministic and stochastic toppling rules. Our results show the existence of two distinct universality classes. We also provide numerical simulations of directed models in the presence of bulk dissipation. The numerical results indicate that the way in which dissipation is implemented is irrelevant for the determination of the critical behavior. The analysis of the self-affine properties of avalanches shows the existence of a subset of superuniversal exponents, whose value is independent of the universality class. This feature is accounted for by means of a phenomenological description of the energy balance …
Absorbing-State Phase Transitions In Fixed-Energy Sandpiles, A Vespignani, R Dickman, M A. Munoz, S Zapperi
Absorbing-State Phase Transitions In Fixed-Energy Sandpiles, A Vespignani, R Dickman, M A. Munoz, S Zapperi
Alessandro Vespignani
We study sandpile models as closed systems, with the conserved energy density zeta playing the role of an external parameter. The critical energy density zeta (c) marks a nonequilibrium phase transition between active and absorbing states. Several fixed-energy sandpiles are studied in extensive simulations of stationary and transient properties, as well as the dynamics of roughening in an interface-height representation. Our primary goal is to identify the universality classes of such models, in hopes of assessing the validity of two recently proposed approaches to sandpiles: a phenomenological continuum Langevin description with absorbing states, and a mapping to driven interface dynamics …