[7p-A410-1~9] 4.9 Quantum Optics

▲ [7p-A410-6] [JSAP-OSA Joint Symposia 2017 Invited Talk] Tying Knots in a Quantum Fluid

〇David S Hall¹, Michael Ray¹, Konstantin Tiurev², Emmi Ruokokoski², Andrei Horia Gheorghe¹, Mikko Mottonen² (1.Amherst Coll., 2.Aalto Univ.)

Keywords:quantum gases, ultracold atoms, topology

Knots are familiar entities that appear at a captivating nexus of art, technology, mathematics, and science. They have recently attracted significant experimental interest, in contexts ranging from knotted DNA and nanostructures to nontrivial vortex knots in classical fluids. Within classical field theories, knots have been proposed as the basis of fundamental particles, as well as explaining diverse persistent phenomena such as atoms and molecules. We describe here the first controlled experimental creation and detection of knot solitons, which are particle-like topological excitations possessing a knotted field character. The superfluid medium is a Bose-Einstein condensate at a temperature some tens of billionths of a degree above absolute zero. In addition to enabling future experimental studies of their properties and dynamics, these knot solitons provide a striking demonstration of the celebrated Hopf fibration, which mathematically ties together many seemingly unrelated physical phenomena.