Ramsey fringes in a Bose-Einstein condensate between atoms and molecules
  In a recent experiment, a Feshbach scattering resonance was exploited to observe Ramsey fringes in a $^{85}$Rb Bose-Einstein condensate. The oscillation frequency corresponded to the binding energy of the molecular state. We show that the observations are remarkably consistent with predictions of a resonance field theory in which the fringes arise from oscillations between atoms and molecules. 
S.J.J.M.F. Kokkelmans, M.J. Holland