Adiabatic evolution for the 87Rb atom–molecule conversion system

The adiabaticity of the stimulated Raman adiabatic passage (STIRAP) for the 87Rb atom–molecule conversion in a condensate system is investigated in terms of a newly defined adiabatic fidelity. The evolution of the dark state in the STIRAP is simulated numerically by considering the interparticle interactions and spontaneous emissions of the excited molecular state. We find that these terms will reduce the adiabatic fidelity; however, one can still achieve higher adiabatic fidelity through optimizing the external parameters of the STIRAP. Our discussions are helpful in obtaining higher conversion efficiency from an atomic Bose–Einstein condensate to its molecular counterpart in experiment.