Coupling between Brownian motion and random walks on the infinite percolation cluster

Chenlin Gu, Zhonggen Su, Ruizhe Xu

Published 2024-11-07Version 1

For the supercritical $\mathbb{Z}^d$-Bernoulli percolation ($d \geq 2$), we give a coupling between the random walk on the infinite cluster and its limit Brownian motion, such that the typical distance between the paths during $[0,T]$ is of order $T^{\frac{1}{3}+o(1)}$. This partially answers an open question posed by Biskup [Probab. Surv., 8:294-373, 2011]. The construction of the coupling utilizes the optimal transport tool, and the analysis relies on local CLT and percolation density concentration. As an application, our result implies the law of the iterated logarithm proved by Duminil-Copin [arXiv:0809.4380], and further identifies the limit constant.