Improved characterization of Feshbach resonances and interaction potentials between <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Na</mml:mi><mml:mprescripts/><mml:none/><mml:mn>23</mml:mn></mml:mmultiscripts></mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Rb</mml:mi><mml:mprescripts/><mml:none/><mml:mn>87</mml:mn></mml:mmultiscripts></mml:math> atoms
Zhichao Guo, Fan Jia, Bing Zhu, Lintao Li, Jeremy M. Hutson, Dajun Wang
Abstract
The ultracold mixture of $^{23}\mathrm{Na}$ and $^{87}\mathrm{Rb}$ atoms has become an important system for investigating physics in Bose-Bose atomic mixtures and for forming ultracold ground-state polar molecules. In this work, we provide an improved characterization of the most commonly used Feshbach resonance near 347.64 G between $^{23}\mathrm{Na}$ and $^{87}\mathrm{Rb}$ in their absolute ground states. We form Feshbach molecules using this resonance and measure their binding energies by dissociating them via magnetic-field modulation. We use the binding energies to refine the singlet and triplet potential-energy curves, using coupled-channel bound-state calculations. We then use coupled-channel scattering calculations on the resulting potentials to produce a high-precision mapping between magnetic field and scattering length. We also observe ten additional $s$-wave Feshbach resonances for $^{23}\mathrm{Na}$ and $^{87}\mathrm{Rb}$ in different combinations of Zeeman sublevels of the $F=1$ hyperfine states. Some of the resonances show two-body inelastic decay due to spin exchange. We compare the resonance properties with coupled-channel scattering calculations that full take account of inelastic properties.