Self-affinity in the gradient percolation problem

Phys Rev E Stat Nonlin Soft Matter Phys. 2007 Mar;75(3 Pt 1):030102. doi: 10.1103/PhysRevE.75.030102. Epub 2007 Mar 16.

Abstract

We study the scaling properties of the solid-on-solid front of the infinite cluster in two-dimensional gradient percolation. We show that such an object is self-affine with a Hurst exponent equal to 23 up to a cutoff length approximately g{-4/7}, where g is the gradient. Beyond this length scale, the front position has the character of uncorrelated noise. Importantly, the self-affine behavior is robust even after removing local jumps of the front. The previously observed multiaffinity is due to the dominance of overhangs at small distances in the structure function. This is a crossover effect.