SKM 2023 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 56: Brownian Motion and Anomalous Diffusion
DY 56.4: Vortrag
Freitag, 31. März 2023, 10:15–10:30, ZEU 160
Apparent anomalous diffusion and non-Gaussian distributions in a simple mobile-immobile transport model with poissonian switching — •Timo J. Doerries1, Aleksei V. Chechkin1,2,3, and Ralf Metzler1 — 1Institute of Physics & Astronomy, University of Potsdam, Germany — 2Faculty of Pure and Applied Mathematics, Hugo Steinhaus Center, Wrocław University of Science and Technology, Wrocław, Poland — 3Akhiezer Institute for Theoretical Physics National Science Center “Kharkiv Institute of Physics and Technology", Kharkiv, Ukraine
We analyse mobile-immobile transport of particles that switch between mobile and immobile states with finite rates. Despite this seemingly simple assumption of Poissonian switching we unveil rich transport dynamics including significant transient anomalous diffusion and non-Gaussian displacement distributions. Our discussion is based on experimental parameters for tau proteins in neuronal cells, but the results obtained here are expected to be of relevance for a broad class of processes in complex systems. Concretely, we obtain that when the mean binding time is significantly longer than the mean mobile time, transient anomalous diffusion is observed at short and intermediate time scales, with a strong dependence on the fraction of initially mobile and immobile particles. We unveil a Laplace distribution of particle displacements at relevant intermediate time scales and the mean squared displacement of mobile tracers displays a plateau. Adding advection to the mobile phase, corresponding to a biosensor with flow, generates a cubic regime of the MSD for high Péclet numbers.