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Usually, when the magnetic field is swept across a Feshbach resonance, the atom pair is adiabatically transferred to the molecular bound state because the two are coupled by the hyperfine interactions in the system. However, in the Na + Li system, such hyperfine-induced Feshbach resonances are at very high magnetic fields that are out of experimental range. Instead, we worked around a Feshbach resonance at 745G that is produced by weak dipole-dipole coupling between the atoms. This coupling term is orders of magnitude weaker than the hyperfine interaction, meaning that the requirements for successful adiabatic conversion of atom pairs to molecules become extraordinarily demanding. However, by carefully controlling our magnetic field stability and sweep sequence, we were able to rapidly jump the field near resonance, do a slow, We are able to create no more than a few percent of our initial atomic mixture to Feshbach molecules only after implementing magnetic field stabilizing circuits by carefully characterizing our experimental system. and adiabatic sweep across the very narrow, ~mG wide range of the Feshbach resonance, and then immediately jump the field away from resonance again to isolate the molecules for imaging. This produced a fraction of NaLi molecules from
We are planning to transfer our initial atomic mixture, and perhaps represents successful molecule formation around the most difficult Feshbach resonance ever used. mixture of atoms to loosely bound molecules via two photon process bridged by a carefully selected excited molecular state.