# 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 Sposini^{1,2}, Aleksei V. Chechkin^{1,3}, and Ralf Metzler^{1} — ^{1}Institute for Physics and Astronomy, University of Potsdam, 14476 Potsdam-Golm, Germany — ^{2}Basque Center for Applied Mathematics, 48009 Bilbao, Spain — ^{3}Akhiezer 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 ⟨*r*^{2}(*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]*.