We predict that a Josephson junction can exhibit, under certain conditions, squeezed or reduced quantum fluctuations of the tunneling current. Using the formal analogy of the Josephson junction to a system of two-level atoms, we show that these reduced fluctuations are closely related to the Bloch-state description of the Bardeen-Cooper-Schrieffer wave function and to the angular-momentum algebra of the proper dynamical variables describing the tunneling process.

• Received 18 January 1985

DOI:https://doi.org/10.1103/PhysRevB.32.4750