DIFFUSION ON RANDOM LATTICES

We study the motion of a point particle along the bonds of a two-dimen sional random lattice, whose sites are randomly occupied with right an d left rotators, which scatter the particle according to deterministic scattering rules. We consider both a Poisson (PRL) and a vectorized r andom lattice (VRL) and fixed as well as flipping scatterers. On both lattices, for fixed scatterers and equal concentrations of right and l eft rotators the same anomalous diffusion of the particle is obtained as before for the triangular lattice, where the mean square displaceme nt is similar to t, the diffusion process non-Gaussian, and the partic le trajectories exhibit scaling behavior as at a percolation threshold . For unequal concentrations the particle is trapped exponentially rap idly. This system can be considered as an extreme case of the Lorentz lattice,eases on regular lattices discussed before or as an example of the motion of a particle along cracks or (grain or cellular) boundari es on a two-dimensional surface.