Hannover 2020 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 34: Quantum gases (Fermions) II

Q 34.2: Talk

Wednesday, March 11, 2020, 14:30–14:45, e214

Direct observation of superfluidity in an ultracold two-dimensional Fermi gas — •Lennart Sobirey, Markus Bohlen, Niclas Luick, Hauke Biss, Thomas Lompe, and Henning Moritz — Institut für Laserphysik, Universität Hamburg, Deutschland

Understanding the mechanism for superfluidity in low dimensional systems with strong correlations is one of the major unsolved problems of condensed matter physics. Ultracold two-dimensional Fermi gases model these systems in a clean and controllable way, but so far, superfluidity has not been directly observed. Here, we present direct evidence of superfluidity in a strongly interacting 2D Fermi gas. We drag an optical lattice through a homogeneous 2D Fermi gas and observe no dissipation below a critical velocity, in excellent agreement with the Landau criterion. We find evidence for superfluidity across a wide range of interaction strengths in the BEC-BCS crossover.