Atomes Et Rayonnement

Collège de FranceJean DalibardChaire Atomes et RayonnementAnnée 2023-2024Séminaire - Rudolf Grimm : Ultracold Fermion Mixtures with Tunable Interactions: Polarons and the Quest for Novel SuperfluidsRudolf GrimmUniversity of Innsbruck and IQOQI, Austrian Academy of Sciences, AutricheRésuméThe possibility to tune interatomic interactions by means of magnetically controlled Feshbach resonances has opened up unprecedented opportunities for experiments concerning the intriguing many-body physics of ultracold matter in the strongly interacting regime. After a brief general introduction, I will report on two main research lines pursued in our laboratories based on fermionic quantum mixtures with tunable interactions.(1) A Fermi sea of Li-6 atoms is doped with impurity atoms of fermionic K-40 or bosonic K-41 atoms, which under strong interactions form quasiparticles. We explore the various properties of these "Fermi polarons" by means of radio-frequency spectroscopy. In our most recent experiments [1], we have observ