  We consider a two-component system of Fermi atoms and molecular bosons in the
vicinity of a Feshbash resonance. We derive an effective action for the system,
which has a term describing coherent tunneling of the molecular bosons into
Cooper pairs and vice versa. In the equilibrium state, global phase coherence
may be destroyed by thermal or quantum phase fluctuations. In the
non-equilibrium regime, the system may show an internal AC Josephson effect
leading to real time oscillations in the number of molecular bosons.
