Please use this identifier to cite or link to this item: doi:10.22028/D291-28640
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Title: Statistics of Colloidal Suspensions Stirred by Microswimmers
Author(s): Ortlieb, Levke
Rafaï, Salima
Peyla, Philippe
Wagner, Christian
John, Thomas
Language: English
Title: Physical review letters
Volume: 122
Issue: 14
Publisher/Platform: APS
Year of Publication: 2019
Publikation type: Journal Article
Abstract: We present a statistical analysis of the experimental trajectories of colloids in a dilute suspension of the green algae Chlamydomonas reinhardtii. The measured probability density function (pdf) of the displacements of colloids covers 7 orders of magnitude. The pdfs are characterized by non-Gaussian tails for intermediate time intervals, but nevertheless they collapse when scaled with their standard deviation. This diffusive scaling breaks down for longer time intervals and the pdf becomes Gaussian. However, the mean squared displacements of tracer positions are linear over the complete measurement time interval. Experiments are performed for various tracer diameters, swimmer concentrations, and mean swimmer velocities. This allows a rigorous comparison with several theoretical models. We can exclude a description based on an effective temperature and other mean field approaches that describe the irregular motion as a sum of the fluctuating far field of many microswimmers. The data are best described by the microscopic model by J.-L. Thiffeault, Distribution of particle displacements due to swimming microorganisms, Phys. Rev. E 92, 023023 (2015)PRESCM1539-375510.1103/PhysRevE.92.023023.
DOI of the first publication: 10.1103/PhysRevLett.122.148101
URL of the first publication:
Link to this record: hdl:20.500.11880/27697
ISSN: 1079-7114
Date of registration: 7-Sep-2019
Faculty: NT - Naturwissenschaftlich- Technische Fakultät
Department: NT - Physik
Professorship: NT - Prof. Dr. Christian Wagner
Collections:SciDok - Der Wissenschaftsserver der Universität des Saarlandes

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