Crossover from directed percolation to compact directed percolation

TL;DR

This paper investigates how surface modifications affect critical spreading in directed percolation models, revealing a transition between universality classes and challenging simple surface effect explanations.

Contribution

It demonstrates a crossover from compact directed percolation to ordinary directed percolation by varying edge growth probabilities, highlighting nonuniversality in models with multiple absorbing states.

Findings

Critical exponents switch between universality classes.

Surface modifications influence critical behavior.

Nonuniversality cannot be solely attributed to surface effects.

Abstract

We study critical spreading in a surface-modified directed percolation model in which the left- and right-most sites have different occupation probabilities than in the bulk. As we vary the probability for growth at an edge, the critical exponents switch from the compact directed percolation class to ordinary directed percolation. We conclude that the nonuniversality observed in models with multiple absorbing configurations cannot be explained as a simple surface effect.