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Fast readout of quantum dot spin qubits via Andreev spins

Michèle Jakob1,*, Katharina Laubscher2,*, Patrick Del Vecchio1, Anasua Chatterjee1, Valla Fatemi3, and Stefano Bosco1,†

  • *These authors contributed equally to this work.
  • †Contact author: s.bosco@tudelft.nl
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Phys. Rev. Applied 26, 034009 – Published 3 September, 2026

DOI: https://doi.org/10.1103/qcch-2hhy

Abstract

Spin qubits in semiconducting quantum dots are currently limited by slow readout processes, which are orders of magnitude slower than gate operations. In contrast, Andreev spin qubits benefit from fast measurement schemes enabled by the large resonator couplings of superconducting qubits but suffer from reduced coherence during qubit operations. Here, we propose fast and high-fidelity measurement protocols based on an electrically tunable coupling between quantum dot and Andreev spin qubits. In realistic devices, this coupling can be made sufficiently strong to enable high-fidelity readout well below microseconds, potentially enabling mid-circuit measurements. Crucially, the electrical tunability of our coupler permits to switch it off during idle periods, minimizing crosstalk and measurement back-action. Our approach is fully compatible with germanium-based devices and paves the way for scalable quantum computing architectures by leveraging the advantages of heterogeneous qubit implementations.

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Phys. Rev. Applied 26, 034009– Published 3 September, 2026
  • Received 22 July 2025
  • Revised 11 June 2026
  • Accepted 5 August 2026
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