Laplacians and Random Walks on CW Complexes

We construct random walks taking place on the k-cells of free G-CW complexes of finite type. These random walks define operators acting on the cellular k-chains that relate nicely to the (upper) cellular k-Laplacian. As an application, we use this relation to show that the Novikov-Shubin invariants of a free G-CW complex X of finite type can be recovered from quantities related to return probabilities of the random walks on the cells of X.