Regensburg 2019 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 43: Anomalous diffusion / Brownian motion

DY 43.5: Vortrag

Donnerstag, 4. April 2019, 11:00–11:15, H3

First passage statistics for Brownian yet non-Gaussian diffusion. — •Vittoria Sposini1,2, Aleksei V. Chechkin1,3, and Ralf Metzler11Institute for Physics and Astronomy, University of Potsdam, 14476 Potsdam-Golm, Germany — 2Basque Center for Applied Mathematics, 48009 Bilbao, Spain — 3Akhiezer Institute for Theoretical Physics, 61108 Kharkov, Ukraine

A rapidly increasing number of systems is identified in which the stochastic motion of tracer particles follows the Brownian law ⟨r2(t) ⟩≃ Dt yet the distribution of particle displacements is strongly non-Gaussian. A central approach to describe this effect is the diffusing diffusivity (DD) model in which the diffusion coefficient itself is a stochastic quantity, mimicking heterogeneities of the environment encountered by the tracer particle on its path. In this talk I will discuss how to quantify, in terms of analytical and numerical approaches, the first passage behaviour of the DD model. We observe significant modifications compared to Brownian-Gaussian diffusion, in particular that the DD model may have a more efficient first passage dynamics. Moreover we find a universal crossover point of the survival probability independent of the initial condition.

[1] Chechkin A V, Seno F, Metzler R & Sokolov I 2017 Brownian Yet Non-Gaussian Diffusion: From Superstatistics to Subordination of Diffusing Diffusivities Phys. Rev. X 7 021002.

[2] Sposini V, Chechkin A V & Metzler R 2018 First passage statistics for diffusing diffusivity arXiv:1809.09186 [cond-mat.stat-mech].

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