University of Connecticut

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Atomic, Molecular, and Optical Physics Seminar

Tuesday, January 20, 2015
3:30pm – 4:30pm

Storrs Campus
Gant Science Complex, Room PB-121

Dr. Rico Pires, Physics Institute, University of Heidelberg

“Efimov Resonances in a Mixture With Extreme Mass Imbalance”

We present the observation of two consecutive heteronuclear Efimov resonances in an ultracold Li-Cs mixture. The resonances are detected in magnetic field dependent three-body loss coefficients and atom loss spectra near a broad Feshbach resonance. The first Efimov resonance is found at a scattering length corresponding to 7 (3) times the Li-Cs (Cs-Cs) van der Waals range. The second resonance appears close to the unitarity-limited regime at the sample temperature of 450 nK. The scaling factor of the resonance positions is close to the predicted universal value of 4.9 for a zero temperature mixture, which is much smaller than the scaling factor for a system of equal mass bosons. Thus, the observation of a third resonance, which allows to confirm the prediction of universal scaling, becomes feasible. Indication of this resonance is found in the atom loss spectra.


Dawn Rawlinson, 486-4916,

Physics Department (primary)

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