Universality classes in directed sandpile models

TL;DR

This study uses large-scale simulations to demonstrate that a directed stochastic sandpile model belongs to a new universality class, highlighting the impact of multiple topplings on critical behavior and advancing understanding of universality in sandpile models.

Contribution

It introduces a new universality class for directed stochastic sandpiles, contrasting it with Abelian models and explaining the role of multiple topplings.

Findings

The stochastic model defines a distinct universality class.

Multiple topplings are key to the different critical behavior.

Results shed light on universality in sandpile models.

Abstract

We perform large scale numerical simulations of a directed version of the two-state stochastic sandpile model. Numerical results show that this stochastic model defines a new universality class with respect to the Abelian directed sandpile. The physical origin of the different critical behavior has to be ascribed to the presence of multiple topplings in the stochastic model. These results provide new insights onto the long debated question of universality in abelian and stochastic sandpiles.