Efficient creation of molecules from a cesium Bose-Einstein condensate

We report a new scheme to create weakly bound $\chem{Cs_2}$ molecules from an atomic Bose-Einstein condensate. The method is based on switching the magnetic field to a narrow Feshbach resonance and yields a high atom-molecule conversion efficiency of more than 30%, a factor of three higher than obtained with conventional magnetic-field ramps. The $\chem{Cs_2}$ molecules are created in a single g-wave rotational quantum state. The observed dependence of the conversion efficiency on the magnetic field and atom density shows scattering processes beyond two-body coupling to occur in the vicinity of the Feshbach resonance