Rarified liquid properties of hybrid atomic-molecular Bose-Einstein condensates

In the atomic Bose-Einstein condensate, the interactions that bring a binar y atom system to an intermediate state molecule in the Feshbach resonance c reate a second condensate component of molecules. The atomic and molecular condensates coherently exchange pairs of atoms. We discuss a signature of t he coherent intercondensate exchange: Josephson-like oscillations of the at omic and molecular populations in response to a sudden change of the energy detuning. The dependence of the many-body ground state energy on volume su ggests that the on-resonant ground state is a dilute condensate with the li quidlike property of a self-determined density.