Distinguishing fractional and white noise in one and two dimensions - art.no. 062102

We discuss the link between uncorrelated noise and the Hurst exponent for o ne- and two-dimensional interfaces. We show that long range correlations ca nnot be observed using one-dimensional cuts through two-dimensional self-af fine surfaces whose height distributions are characterized by a Hurst expon ent H lower than-1/2. In this domain, fractional and white noise are not di stinguishable. A method analyzing the correlations in two dimensions is nec essary. For H>-1/2, a crossover regime leads to an systematic overestimate of the Hurst exponent.