Many-body effects on adiabatic passage through Feshbach resonances (9 pages)

A. P. Itin, A. A. Vasiliev, G. Krishna +1 more

Hong Yuan Ling, Han Pu, Brian Seaman

We study the Feshbach resonance assisted stimulated adiabatic passage of an effective coupling field for creating stable molecules from an atomic Bose condensate. By exploring the properties of the coherent population trapping state, we show that, contrary to the previous belief, mean-field shifts need not limit the conversion efficiency as long as one chooses an adiabatic passage route that compensates the collision mean-field phase shifts and avoids the dynamical unstable regime.

Angelo Russomanno, Emanuele G. Dalla Torre

Pengjun Wang, Zhengkun Fu, Shijie Chai +1 more

We report the experimental preparations of the absolute ground states of 87 Rb and 40 K atoms (| F = 1, m F = 1〉 + | F = 9/2, m F = −9/2〉) by means of the radio-frequency and microwave adiabatic rapid passages, and the observation of magnetic Feshbach resonances in an ultracold mixture of bosonic 87 Rb and fermionic 40 K atoms between 0 T and 6.0 × 10 −2 T, including 7 homonuclear and 4 heteronuclear Feshbach resonances. The resonances are identified by the abrupt trap loss of atoms induced by the strong inelastic three-body collisions. These Feshbach resonances should enable the experimental control of interspecies interactions.

G. M. Falco, Henk T. C. Stoof

Matt Mackie, Olavi Dannenberg

We theoretically examine a zero-temperature system of Fermi degenerate atoms coupled to bosonic molecules via collisionless rapid adiabatic passage across a Feshbach resonance, focusing on saturation of the molecular conversion efficiency at the slowest magnetic-field sweep rates. Borrowing a novel MANY-FERMION Fock-state theory, we find that a proper model of the magnetic-field sweep can systematically remove saturation. We also debunk the common misconception that many-body effects are responsible for molecules existing above the two-body threshold.