Group Seminar via Zoom: Magneto-association of NaK Feshbach molecules

May 26, 2020

Marcel Duda, MPQ
group meeting via Videoconference (Zoom)
Tuesday, May 26th, 09:00 (MEZ)

Dealing with the unique situation of partial lock downs worldwide and home office solutions at our Institute due to the current spreading of the Covid 19 virus, we are now holding our group seminars and journal clubs via video conference. This procedure enables us to continue our research, enhance discussions and exchange important information.


Association of Feshbach molecules with a Bose-Fermi mixture is, due to the bad phase-space overlap and inelastic losses, an inherently difficult task. Even more so, once the bosons undergo Bose-Einstein condensation. When associating our atoms by a radio-frequency pulse, we are able to create 15000 Feshbach molecules and the association efficiency quickly drops below the critical temperature for sodium. We report on the implementation of magneto-association in our system where Feshbach molecules are created by sweeping the magnetic field over a Feshbach resonance. We show that starting from a mixture of degenerate potassium and sodium near the critical temperature, we associate 40000 Feshbach molecules at 0.7TF, increasing the phase-space density by an order of magnitude. We discuss the difficulties to associate potassium atoms in the presence of a sodium BEC where we experience 50% loss in sodium. We characterize the three-body recombination rates, indicating atom-dimer loss to be the major loss process.

If you would like to join our group seminars via Zoom, please contact us for more information.

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