Spectral dimension of branched structures: Universality in geometrical disorder

Abstract
By analytically studying random walk generating functions on a wide class of disordered branched structures we obtain the exact values of their spectral dimensions, which turn out to depend only on the branching degree of these structures. The results show that the spectral dimension is a universal quantity largely disorder independent provided that some boundedness conditions are satisfied; its values are also always less than 2, so that these branched structures are all recursive graphs.