Coupled superconducting spin qubits with spin-orbit interaction

Abstract

Superconducting spin qubits, also known as Andreev spin qubits, promise to combine the benefits of superconducting qubits and spin qubits defined in quantum dots. While most approaches to control these qubits rely on controlling the spin degree of freedom via the supercurrent, superconducting spin qubits can also be coupled to each other via the superconductor to implement two-qubit quantum gates. We theoretically investigate the interaction between superconducting spin qubits in the weak tunneling regime and concentrate on the effect of spin-orbit interaction (SOI), which can be large in semiconductor-based quantum dots and thereby offers an additional tuning parameter for quantum gates. We find analytically that the effective interaction between two superconducting spin qubits consists of Ising, Heisenberg, and Dzyaloshinskii-Moriya interactions and can be tuned by the superconducting phase difference, the tunnel barrier strength, or the SOI parameters. The Josephson current becomes dependent on SOI and spin orientations. We demonstrate that this interaction can be used for fast controlled phase-flip gates with a fidelity >99.99%. We propose a scalable network of superconducting spin qubits which is suitable for implementing the surface code.

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Cited by in corpus (18)

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• Hard superconducting gap in germanium
• Spectroscopy of spin-split Andreev levels in a quantum dot with superconducting leads
• Strong tunable coupling between two distant superconducting spin qubits
• A gate tunable transmon qubit in planar Ge
• Phase-dependent Andreev molecules and superconducting gap closing in coherently coupled Josephson junctions
• High-fidelity two-qubit gates of hybrid superconducting-semiconducting singlet-triplet qubits
• Blueprint for all-to-all connected superconducting spin qubits
• From perfect to imperfect poor man's Majoranas in minimal Kitaev chains
• Microscopic analysis of proximity-induced superconductivity and metallization effects in superconductor-germanium hole nanowires
• Coupling of quantum-dot states via elastic-cotunneling and crossed Andreev reflection in a minimal Kitaev chain
• Fabry-Perot superconducting diode
• A particle conserving approach to AC-DC driven interacting quantum dots with superconducting leads
• Spin-resolved nonlocal transport in proximitized Rashba nanowires
• Relations between normal state nonreciprocal transport and the superconducting diode effect in the trivial and topological phases
• Heavy-hole spin relaxation in quantum dots: Isotropic versus anisotropic effects
• Andreev qubit readout from dynamic interference supercurrent