Multi-terminal superconducting phase qubit

Mesoscopic multi-terminal Josephson junctions are novel devices that provide weak coupling between several bulk superconductors through a common normal layer. Because of the nonlocal coupling of the superconducting banks. a current flow, between two of the terminals can induce a phase difference and/or current flow in the other terminals, This "phase dragging" effect is used in designing a new, type of superconducting phase qubit, the basic element of a quantum computer. Time-reversal synimetry breaking can be achieved by inserting a pi-phase shifter into the flux loop, Logical operations are done by applying currents. This removes the necessity for local external magnetic fields to achieve bistability or controllable operations. (C) 2001 Elsevier Science B.V. All rights reserved.