We consider an analog of the internal Josephson effect in superfluid atomic Fermi gases. Four different hyperfine states of the atoms are assumed to be trapped and to form two superfluids via the BCS type of pairing. We show that Josephson oscillations can be realized by coupling the superfluids with two laser fields. Choosing the laser detunings in a suitable way leads to an asymmetric below-gap tunneling effect for which there exists no analog in the context of solid-state superconductivity.

• Received 17 April 2002

DOI:https://doi.org/10.1103/PhysRevA.66.041603