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Very high precision bound state spectroscopy near a $^{85}$Rb Feshbach resonance

N. R. Claussen·S. J. J. M. F. Kokkelmans·S. T. Thompson·E. A. Donley·C. E. Wieman
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Abstract

We precisely measured the binding energy of a molecular state near the Feshbach resonance in a $^{85}$Rb Bose-Einstein condensate (BEC). Rapid magnetic field pulses induced coherent atom-molecule oscillations in the BEC. We measured the oscillation frequency as a function of B-field and fit the data to a coupled-channels model. Our analysis constrained the Feshbach resonance position [155.041(18) G], width [10.71(2) G], and background scattering length [-443(3) a$_0$] and yielded new values for $v_{DS}$, $v_{DT}$, and $C_6$. These results improved our estimate for the stability condition of an attractive BEC. We also found evidence for a mean-field shift to the binding energy.

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N. R. Claussen, S. J. J. M. F. Kokkelmans, S. T. Thompson, E. A. Donley, C. E. Wieman. 2003-02-11. Very high precision bound state spectroscopy near a $^{85}$Rb Feshbach resonance. https://doi.org/10.1103/physreva.67.060701

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