Feshbach resonances, weakly bound molecular states, and coupled-channel potentials for cesium at high magnetic fields

Abstract

Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. We explore the scattering properties of ultracold ground-state Cs atoms at magnetic fields between 450 G (45 mT) and 1000 G. We identify 17 previously unreported Feshbach resonances, including two very broad ones near 549 and 787 G. We measure the binding energies of several different dimer states by magnetic field modulation spectroscopy. We use least-squares fitting to these experimental results, together with previous measurements at lower field, to determine a six-parameter model of the long-range interaction potential, designated M2012. Coupled-channels calculations using M2012 provide an accurate mapping between the s-wave scattering length and the magnetic field over the entire range of fields considered. This mapping is crucial for experiments that rely on precise tuning of the scattering length, such as those on Efimov physics.

Contrasting the wide Feshbach resonances inLi6andLi7

“…IV of Ref. [45], so it will not be repeated here. The basis sets included all functions for L = 0 and L = 2 with the required…”

“…We define S (7) S = S (6) S + S S and fit to the four parameters S (6) 0 , S 0 , S (6) 1 , and S 1 . In principle we could also fit to additional parameters such as C 6 , C 8 , etc., as was done for Cs [45], but this was not found to be necessary to reproduce the threshold results for Li.…”

Three-body parameter for Efimov states inLi6

“…Quantitative understanding of these resonances requires both very precise knowledge of the two-body scattering properties and an accurate theoretical description of finite-temperature effects. Reference [42] analyzed the excited-state Efimov resonance in cesium using a highly accurate model of the two-body scattering [43] and a theoretical finite-temperature approach recently developed in Ref. [41].…”

Observation of interspecies Feshbach resonances in an ultracold K39−Cs133 mixture and refinement of interaction potentials

“…The individual two-body interaction properties of 39 K [43] and Cs [44,45] are well understood. This has allowed the production of Bose-Einstein condensates for each species separately [4,[46][47][48] and for both species in the same apparatus [49].…”