18-21 September 2019
Kraków
Europe/Warsaw timezone

Mimicking heterogeneous diffusion with time dependent random diffusivity.

19 Sep 2019, 12:00
20m
Kraków

Kraków

Talk Session 3

Speaker

Ms. Vittoria Sposini (University of Potsdam (Germany) & BCAM (Spain))

Description

A considerable number of systems have recently been reported in which Brownian yet non-Gaussian dynamics was observed. These are processes characterised by a linear growth in time of the mean squared displacement, yet the probability density function of the particle displacement is distinctly non-Gaussian, and often of exponential (Laplace) shape. This behaviour has been interpreted as resulting from diffusion in inhomogeneous environments and mathematically represented through a variable, stochastic diffusion coefficient. Indeed different models describing a fluctuating diffusivity have been studied. In particular, we focus on the theory of diffusing diffusivity and consider the very generic class of the generalised Gamma distribution for the random diffusion coefficient. Moreover, addressing the first passage problem for a specific diffusing diffusivity model, we emphasize that even when the non-Gaussian character appears for certain regimes only and in the tails of the distributions (thus with low probability), it may be essential for those systems in which rare events dominate triggered actions.

Primary author

Ms. Vittoria Sposini (University of Potsdam (Germany) & BCAM (Spain))

Co-authors

Mr. Gianni Pagnini (BCAM & Ikerbasque ) Prof. Ralf Metzler (University of Potsdam) Prof. Aleksei Chechkin (University of Potsdam & Akhiezer Institute for Theoretical Physics )

Presentation Materials

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