Dresden 2020 – wissenschaftliches Programm
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DY 37.5: Vortrag
Mittwoch, 18. März 2020, 11:00–11:15, ZEU 160
Lorentz forces induce inhomogeneity and flux in active systems — •Hidde Vuijk1, Jens-Uwe Sommer1,2, Holger Merlitz1, Joseph Brader3, and Abhinav Sharma1,2 — 1Leibniz Institute of Polymer Research, Dresden, Germany — 2Technische Universität Dresden, Dresden, Germany — 3Universite de Fribourg, Fribourg, Switserland
We consider the dynamics of a charged active Brownian particle in three dimensions subjected to the Lorentz force due to an external magnetic field. We show that in the presence of a field gradient, a macroscopic flux emerges from a flux-free system and the density distribution becomes inhomogeneous. The flux is induced by the gradient of the magnetic field only and does not require additional symmetry breaking such as density or potential gradients, which stands in marked contrast to similar phenomena in condensed matter such as the classical Hall effect. We further demonstrate that passive tracer particles can be used to measure the essential effects caused by the Lorentz force on the active particle bath, and we discuss under which conditions this diffusive Hall-like effect might be observed experimentally. Lastly, we show that similar effects arise in case of inhomogeneous activity in combination with a constant magnetic field.