Formation of a molecular Bose-Einstein condensate and an entangled atomic gas by time-dependent Feshbach resonance.

Association in an atomic Bose-Einstein condensate, and the subsequent dissociation of the resulting molecular condensate, due to Feshbach resonance in a time-dependent magnetic field, are analyzed, incorporating non-mean-field quantum corrections and inelastic collisions. Calculations for the Na atomic condensate demonstrate that there exist optimal conditions under which about 80% of the atomic population can be converted to a relatively long-lived molecular condensate (with lifetimes of 10 ms and longer), if the magnetic field is temporally changed one way. Entangled atoms in two-mode squeezed states (with noise reduction of about 30 dB) are formed by molecular dissociation when the field is changed the other way.