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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 17: Liquid Crystals
CPP 17.2: Vortrag
Dienstag, 15. März 2011, 14:30–14:45, ZEU 114
Reconfigurable knots and links in chiral nematic fluids — •Uroš Tkalec1,2, Simon Čopar3, Miha Ravnik3,4, Slobodan Žumer3,2, and Igor Muševič2,3 — 1Max-Planck-Institute for Dynamics and Self-organization, Göttingen, Germany — 2Jožef Stefan Institute, Ljubljana, Slovenia — 3Faculty of Mathematics and Physics, Ljubljana, Slovenia — 4Rudolf Peierls Centre for Theoretical Physics, Oxford, United Kingdom
Creation and control of non-trivial topological objects is important in various biological and condensed matter systems. However, detailed studies of knotted structures in all these systems remain challenging due to their inherent smallness and typically large but poorly controllable ensemble of configurations. We show that knots and links of fascinating complexity can be realized and specifically reconfigured in the molecular orientational field of chiral nematic liquid crystal using optical manipulation of topological defect loops, which are spanned on ordered microparticle arrays. We also unveil a simple reknitting mechanism, based on a tetrahedral rotation of two relevant disclination segments, that allows us to predict and topologically characterize all available entangled configurations. These principles reveal a novel manifestation of knot theory in a concrete physical phenomenon and offer a way to interpret akin topological structures in physically analogous condensed matter systems.