d-Wave superconductors and quantum computers

Luca Dell’Anna

Yonuk Chong, Jaewoo Joo

Alexandre Blais, Alexandre M. Zagoskin

The operation of a solid-state superconducting quantum computer based on clean Josephson junctions between two d-wave superconductors is considered. We show that freezing of passive qubits can be achieved using a dynamic global refocusing technique. Further, we demonstrate that a universal set of gates can be realized on this system, thereby proving its universality.

Matthias Vojta C, Subir Sachdev A

Jun-Feng Liu, Yong Xu, Jun Wang

Abstract We propose the Josephson junctions linked by a normal metal between a d + id superconductor and another d + id superconductor, a d-wave superconductor, or a s-wave superconductor for identifying the chiral d + id superconductivity. The time-reversal breaking in the chiral d-wave superconducting state is shown to result in a Josephson φ0-junction state where the current-phase relation is shifted by a phase φ0 from the sinusoidal relation, other than 0 and π. The ground-state phase difference φ0 and the critical current can be used to definitely confirm and read the information about the d + id superconductivity. A smooth evolution from conventional 0-π transitions to tunable φ0-states can be observed by changing the relative magnitude of two types of d-wave components in the d + id pairing. On the other hand, the Josephson junction involving the d + id superconductor is also the simplest model to realize a φ0- junction, which is useful in superconducting electronics and superconducting quantum computation.

Chuck Easttom