Condensed Matter Physics (Mar 2017)
Scaling laws for random walks in long-range correlated disordered media
Abstract
We study the scaling laws of diffusion in two-dimensional media with long-range correlated disorder through exact enumeration of random walks. The disordered medium is modelled by percolation clusters with correlations decaying with the distance as a power law, r^{-a}, generated with the improved Fourier filtering method. To characterize this type of disorder, we determine the percolation threshold p_c by investigating cluster-wrapping probabilities. At p_c, we estimate the (sub-diffusive) walk dimension d_w for different correlation exponents a. Above p_c, our results suggest a normal random walk behavior for weak correlations, whereas anomalous diffusion cannot be ruled out in the strongly correlated case, i.e., for small a.
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