Figure 2: The d-wave Feshbach resonance.

(a) The theoretical K-Rb scattering length, a_K-Rb, is shown as a function of the magnetic field for the broad s-wave Feshbach resonance and a narrow d-wave resonance, based on the formula and parameter values described in Methods. (b) Crossing the d-wave resonance affects the pair states for K and Rb. Dashed and solid arrows show the effect of the variable rate sweep that creates doublons and the subsequent fast magneto-association sweep, respectively. Dashed vertical lines mark the positions of the Feshbach resonances. (c) Measurement of molecule conversion efficiency at 35 E_R (circles) and 30 E_R (diamonds), with the latter data exponentiated by (35/30)^3/4=1.12 to account for the expected dependence on lattice depth. The solid curve shows a fit to a Landau-Zener probability P (see text), which gives a resonance width of 9.3(7) × 10⁻⁴ mT. (d) The magnetic field at which this resonance occurs is determined by sweeping up to various fields at 0.018 mT ms⁻¹, then sweeping down at 0.18 mT ms⁻¹. The position of the resonance extracted from this measurement at V_latt=35E_R is 54.747(1) mT. All error bars represent 1−σ standard error.