Hauptseminar Active Matter SS 2017/Active Particles in External Fields

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Datum
2017-05-24
Zeit
17:30
Thema
Active Particles in External Fields
Vortragender
Philipp Lunt
Betreuer
J. Ruben Gomez-Solano
Handout
[1]

Contents

Microswimmers move autonomously but are subject to external fields, which influence their swimming path and their collective dynamics. In this topic, we illustrate swimming in external fields with three concreate examples and explain the methodology to treat it [1]. First, an active Brownian particle shows a conventional sedimentation profile in a gravitational field but with increased sedimentation length and some polar order along the vertical. Bottom-heavy swimmers are able to invert the sedimentation profile [2-4]. Second, active Brownian particles interacting by hydrodynamic flow fields in a three-dimensional harmonic trap can spontaneously break the isotropic symmetry [5]. Third, the characterization of synthetic self-propelled particles under an external shear flow. Under certain conditions, particles exhibit “rheotaxis”, i.e., they align their direction of motion with the plane of shear spanned by the direction of the flow and the normal of the bounding surface and move with or against the flow [6-7].

Literature

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  3. M. Enculescu and H. Stark. Phys. Rev. Lett. 107, 058301 (2011).
  4. B. ten Hagen, F. Kümmel, R. Wittkowski, D. Takagi, H. Löwen, and C. Bechinger. Nature Comm. 5, 4829 (2014).
  5. M. Hennes, K. Wolff, H. Stark, Phys. Rev. Lett. 112, 238104 (2014).
  6. J. Palacci, A. Abramian, S. Sacanna, J. Barral, K. Hanson, A.Y. Grosberg, D.J. Pine, P.M. Chaikin, Science Advances, 1, 2015.
  7. W. E. Uspal, M. N. Popescu, S. Dietrich and M. Tasinkevych. Soft Matter, 11, 6613-6632 (2015).