Production and Decay of Ultracold Feshbach Molecules in Bosonic and Fermionic Species.

E. Pazy, Amichay Vardi, Y. B. Band

J. Cubizolles, SALOMON, Christophe

E. Hodby, Sarah T. Thompson, Cindy A. Regal +5 more

We investigate the production efficiency of ultracold molecules in bosonic 85Rb and fermionic 40K when the magnetic field is swept across a Feshbach resonance. For adiabatic sweeps of the magnetic field, our novel model shows that the conversion efficiency of both species is solely determined by the phase space density of the atomic cloud, in contrast with a number of theoretical predictions. In the nonadiabatic regime our measurements of the 85Rb molecule conversion efficiency follow a Landau-Zener model.

Thorsten Köhler, Thomas M. Hanna, Hugo E. L. Martay

Thomas M. Hanna, Hugo E. L. Martay, Thorsten Köhler

E. Hodby, Sarah T. Thompson, Cindy A. Regal +5 more

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 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.