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Selected Works

Alessandro Vespignani

Selected Works

2012

Critical behavior

Articles 1 - 2 of 2

Full-Text Articles in Physics

Critical Behavior And Conservation In Directed Sandpiles, R Pastor-Satorras, A Vespignani Feb 2012

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 …


Critical Behavior Of A One-Dimensional Fixed-Energy Stochastic Sandpile, R Dickman, M Alava, M A. Munoz, J Peltola, A Vespignani, S Zapperi Feb 2012

Critical Behavior Of A One-Dimensional Fixed-Energy Stochastic Sandpile, R Dickman, M Alava, M A. Munoz, J Peltola, A Vespignani, S Zapperi

Alessandro Vespignani

We study a one-dimensional fixed-energy version (that is, with no input or loss of particles) of Manna's stochastic sandpile model. The system has a continuous transition to an absorbing state at a critical value of the particle density, and exhibits the hallmarks of an absorbing-state phase transition, including finite-size scaling. Critical exponents are obtained from extensive simulations, which treat stationary and transient properties, and an associated interface representation. These exponents characterize the universality class of an absorbing-state phase transition with a static conserved density in one dimension; they differ from those expected at a linear-interface depinning transition in a medium …