The flux shuttle—A Josephson junction shift register employing single flux quanta

A shift register is described which employs as information bits the flux quantum vortices occurring in Josephson junctions of extended dimensions. The positions of the vortices can be controlled and manipulated by an appropriately designed circuit geometry and by application of currents and magnetic fields. The time required for switching of the position of a vortex can approach the period of the Josephson plasma oscillation (∼10 ps) and the intrinsic energy dissipation is typically ≲ 10^-18J/shift.