Few-body ultracold reactions in a Bose-Fermi mixture

Department of Physics and JILA, University of Colorado, Boulder, Colorado 80309-0440, USA(Dated: January 27, 2012)The spectrum of two bosons and two fermions in a trap is calculated using a correlated-Gaussianbasis throughout the range of a broad Fano-Feshbach resonance. The calculations provide a few-body solution to the magneto-association of fermionic Feshbach molecules. This solution is usedto study the time evolution of the system as the scattering length changes, mimicking experimentswith Bose-Fermi mixtures near Fano-Feshbach resonances. The structure of avoided crossings inthe few-body spectrum enables an interpretation of the dynamics of the system as a sequence ofLandau-Zener transitions. The calculated molecule formation rate is compared with experimentalobservations.I. INTRODUCTION