Mesoscopic d-Wave Qubits: Can High-T_c Cuprates Play a Role in Quantum Computing?

Authors: ALEXANDRE M. ZAGOSKIN

Abstract: Due to nontrivial orbital pairing symmetry, surfaces and interfaces of high-T_c superconductors support states which violate time-reversal (T-) symmetry. Such naturally degenerate states, useful as working states of a qubit, are standard for atomic or molecular-size qubit prototypes (e.g. based on nuclear spins), but exceptional for mesoscopic qubits. (In particular, they hold promise of a better scalability.) In these lectures I review the physics of T-breaking on surfaces and interfaces of high-T_c superconductors; then describe existing proposals for high-T_c based qubits and the current state of experiments; finally, I discuss the decoherence sources in the system, open questions, and future research directions.

Keywords: high-T_c, Josephson, T-breaking, d-wave, qubit, decoherence, design, scalability

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