Coherent Population Exchange between BCS Atom Pairs and Ground Molecular BEC Atom Pairs

Two fermionic atoms of opposite spins (represented by the hyperfine Zeeman sublevels)~can be combined either into a molecule highly localized in real space or into a Bardeen-Cooper-Schrieffer (BCS) pair highly correlated in momentum space.~ In an attractive fermionic system with atoms of opposite spins, we show that the simultaneous presence of a Feshbach resonance and an optical laser coupling can lead to a coherent superposition between the ground molecular state and the~BEC state.~By optically perturbing the system, we demonstrate numerically stable~coherent atom-molecule oscillations.