Hannover 2020 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 34: Quantum gases (Fermions) II
Q 34.3: Talk
Wednesday, March 11, 2020, 14:45–15:00, e214
An ideal Josephson junction in an ultracold two-dimensional Fermi gas — •Niclas Luick1,2, Lennart Sobirey1,2, Markus Bohlen1,2,3, Vijay Pal Singh4,2, Ludwig Mathey4,2, Thomas Lompe1,2, and Henning Moritz1,2 — 1Institut für Laserphysik, Universität Hamburg — 2The Hamburg Centre for Ultrafast Imaging, Universität Hamburg — 3Laboratoire Kastler Brossel, ENS-PSL Research University, CNRS, Sorbonne Université, Collège de France, 24 rue Lhomond, 75005 Paris, France — 4Zentrum für optische Quantentechnologien, Universität Hamburg
Two-dimensional structures are present in almost all known superconductors with high critical temperatures, but the role of the reduced dimensionality is still under debate. Recently, ultracold atoms have emerged as an ideal model system to study such strongly correlated 2D systems.
Here, we present our realisation of a Josephson junction in an ultracold 2D Fermi gas. We measure the frequency of Josephson oscillations as a function of the phase difference across the junction and find excellent agreement with the sinusoidal current phase relation of an ideal Josephson junction. Furthermore, we determine the critical current of our junction in the crossover from tightly bound molecules to weakly bound Cooper pairs. Our measurements clearly demonstrate phase coherence and provide strong evidence for superfluidity in a strongly interacting 2D Fermi gas.