Biased diffusion in percolation systems: indication of multifractal behaviour

摘要: The authors study diffusion in percolation systems at criticality the presence of a constant bias field E. Using exact enumeration method they show that mean displacement random walker varies as (r(t)) approximately log t/A(E) where A/(E)=In((1+E)/(1-E)) for small More generally, on given configuration is characterised by probability P(r,t) site r time t. They find corresponding configurational average shows simple scaling behaviour and described single exponent. In contrast their numerical results indicate averaged moments (Pq(t))= Sigma rPq(r,t)) are an infinite hierarchy exponents. For zero field, however, all determined gap