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arXiv:1810.12453 · Physical Review A

Feshbach resonances in potassium Bose-Bose mixtures

Luca Tanzi, Cesar R. Cabrera, J. Sanz, P. Cheiney, Michał Tomza, Leticia Tarruell

Published Dec 26, 2018• 63 citations
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Abstract

We present a detailed study of the scattering properties of ultracold mixtures of bosonic potassium atoms. We locate 20 previously unobserved Feshbach resonances in isotopic $^{39}\mathrm{K}\text{\ensuremath{-}}^{41}\mathrm{K}$ mixtures. These are assigned to $s$-wave molecular channels by comparison to an asymptotic bound state model and coupled-channel calculations. Additional Feshbach resonances are studied in spin mixtures of a single potassium isotope, both in $^{39}\mathrm{K}$ and $^{41}\mathrm{K}$. In particular, we characterize the parameters of a selected $^{39}\mathrm{K}$ Feshbach resonance by radio-frequency association of Feshbach molecules. Our results could be exploited to refine the model potentials for potassium scattering. Furthermore, these new Feshbach resonances enlarge the range of experiments possible with degenerate Bose-Bose mixtures.

DOI
10.1103/physreva.98.062712

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We observe interspecies Feshbach resonances due to sss-wave bound states in ultracold $^{39}\mathrm{K}\ensuremath{-}^{133}\mathrm{Cs}$ scattering for three different spin mixtures. The resonances are observed as joint atom loss and heating of the K sample. We perform least-squares fits to obtain improved K-Cs interaction potentials that reproduce the observed resonances, and carry out coupled-channel calculations to characterize the scattering and bound-state properties for 39K^{39}\mathrm{K}39K-Cs, 40K^{40}\mathrm{K}40K-Cs, and 41K^{41}\mathrm{K}41K-Cs. Our results open up the possibilities of tuning interactions in K-Cs atomic mixtures and of producing ultracold KCs molecules.
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