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Production Efficiency of Ultracold Feshbach Molecules in Bosonic and Fermionic Systems

E. Hodby·S. T. Thompson·C. A. Regal·M. Greiner·A. C. Wilson·D. S. Jin·E. A. Cornell·C. E. Wieman
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Abstract

We investigate the production efficiency of ultracold molecules in bosonic $^{85}$Rb and fermionic $^{40}$K when the magnetic field is swept across a Feshbach resonance. For adiabatic sweeps of the magnetic field, the conversion efficiency of each species is solely determined by the phase space density of the atomic cloud, in contrast to a number of theoretical predictions. Our novel model for the adiabatic pairing process, developed from general physical principles, accurately predicts the conversion efficiency for {\it both} ultracold gases of bosons and of fermions. In the non-adiabatic regime our measurements of the $^{85}$Rb molecule conversion efficiency follow a Landau Zener model, with a conversion efficiency that is characterized by the density divided by the time derivative of the magnetic field.

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E. Hodby, S. T. Thompson, C. A. Regal, M. Greiner, A. C. Wilson, D. S. Jin, E. A. Cornell, C. E. Wieman. 2004-12-03. Production Efficiency of Ultracold Feshbach Molecules in Bosonic and Fermionic Systems. https://doi.org/10.1103/physrevlett.94.120402

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