Loop-Erased Random Walk and Poisson Kernel on Planar Graphs

Lawler, Schramm and Werner showed that the scaling limit of the loop-erased random walk on Z2 is SLE2. We consider scaling limits of the loop-erasure of random walks on other planar graphs (graphs embedded into C so that edges do not cross one another). We show that if the scaling limit of the random walk is planar Brownian motion, then the scaling limit of its loop-erasure is SLE2. Our main contribution is showing that for such graphs, the discrete Poisson kernel can be approximated by the continuous one. One example is the infinite component of super-critical percolation on Z2. Berger and Biskup showed that the scaling limit of the random walk on this graph is planar Brownian motion. Our results imply that the scaling limit of the looperased random walk on the super-critical percolation cluster is SLE2. Faculty of Mathematics and Computer Science, The Weizmann Institute of Science, Rehovot 76100, Israel. E-mail: [email protected]. Faculty of Mathematics and Computer Science, The Weizmann Institute of Science, Rehovot 76100, Israel. E-mail: [email protected]. Research supported by a grant from the Israel Ministry of Science (IMOS) Eshkol Fellowship. 1