Type transition of simple random walks on randomly directed regular lattices

Abstract

Simple random walks on a partially directed version of ${\mathbb{Z}}^2$ are considered. More precisely, vertical edges between neighbouring vertices of ${\mathbb{Z}}^2$ can be traversed in both directions (they are undirected) while horizontal edges are one-way. The horizontal orientation is prescribed by a random perturbation of a periodic function, the perturbation probability decays according to a power law in the absolute value of the ordinate. We study the type of the simple random walk, i.e.\ its being recurrent or transient, and show that there exists a critical value of the decay power, above which the walk is almost surely recurrent and below which is almost surely transient.

Accepted for publication in Journal of Applied Probability (2014)