2009/04/30 by Nicolas Mercadier, William Guerin, Martine Chevrollier +1 · 1 citation
Physics and Astronomy · #physics.atom-ph #cond-mat.stat-mech #physics.optics
paper · pdf · doi:10.1038/nphys1286
published as Nature Physics 5 (2009) 602 · This final version is identical to the one published in Nature Physics
arxiv created 2009/11/17 · arxiv updated 2015/05/13
Properties of random and fluctuating systems are often studied through the use of Gaussian distributions. However, in a number of situations, rare events have drastic consequences, which can not be explained by Gaussian statistics. Considerable efforts have thus been devoted to the study of non Gaussian fluctuations such as Lévy statistics, generalizing the standard description of random walks. Unfortunately only macroscopic signatures, obtained by averaging over many random steps, are usually observed in physical systems. We present experimental results investigating the elementary process of anomalous diffusion of photons in hot atomic vapours. We measure the step size distribution of the random walk and show that it follows a power law characteristic of Lévy flights.