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DY: Fachverband Dynamik und Statistische Physik
DY 80: Brownian Motion and Transport
DY 80.3: Talk
Friday, March 16, 2018, 10:30–10:45, BH-N 128
Anomalies, Rare Events, and Brownian Motion — Jose M. Miotto1, Simone Pigolotti2, Aleksei V. Chechkin3, 4, and •Sandalo Roldan-Vargas5 — 1Leiden Institute of Advanced Computer Science, Leiden University, Netherlands — 2Okinawa Institute for Science and Technology, Japan — 3Institute for Physics and Astronomy, University of Potsdam, Germany — 4Akhiezer Institute for Theoretical Physics, Kharkov, Ukraine — 5Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
In one of his celebrated 1905 papers, Albert Einstein proposed for the first time a statistical interpretation of Robert Brown innocent observation based on the corpuscular constitution of matter. His theory suggested that the long time motion of a Brownian particle is diffusive whereas the probability distribution of the particle displacements is Gaussian. For more than one hundred years these predictions were systematically validated in real systems and the coexistence between Diffusivity and Gaussianity became a paradigm. However, recent experiments on mesoscopic particle systems have claimed the existence of a time regime where diffusion is not accompanied by a purely Gaussian distribution of displacements. By molecular dynamics simulations of 2- and 3-D glass and gel forming-liquids we show the emergence of a non-Gaussian exponential tail in the probability distribution of particle displacements whose exponential rate is dimension dependent. We further show that the diffusive regime accompanying the non-Gaussian distribution of displacements is the result of a mixture of anomalous diffusivities.