Dynamics of a linear magnetic “microswimmer molecule”
Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf - Universitätsstraße 1, D-40225 Düsseldorf, Germany
Received: 12 November 2015
Accepted: 18 March 2016
In analogy to nanoscopic molecules that are composed of individual atoms, we consider an active “microswimmer molecule”. It is made of three individual magnetic colloidal microswimmers that are connected by harmonic springs and interact hydrodynamically. In the ground state, they form a linear straight molecule. We analyze the relaxation dynamics for perturbations of this straight configuration. As a central result, with increasing self-propulsion, we observe an oscillatory instability in accord with a subcritical Hopf bifurcation scenario. It is accompanied by a corkscrew-like swimming trajectory of increasing radius. Our results can be tested experimentally, using, for instance, magnetic self-propelled Janus particles, supposably linked by DNA molecules.
PACS: 82.70.Dd – Colloids / 47.63.Gd – Swimming microorganisms / 47.20.Ky – Nonlinearity, bifurcation, and symmetry breaking
© EPLA, 2016