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Hole-spin qubits in germanium beyond the single-particle regime

Andrea Secchi1,*, Gaia Forghieri1,2,†, Paolo Bordone1,2, Daniel Loss3,4,5,6, Stefano Bosco7, and Filippo Troiani1

  • *Contact author: andrea.secchi@nano.cnr.it
  • †Present address: Dipartimento di Fisica, Università di Milano, I-20133 Milan, Italy.
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Phys. Rev. Applied 26, 054031 – Published 10 November, 2026

DOI: https://doi.org/10.1103/9w1z-8x7g

Abstract

So far, intense simulation efforts on hole-spin qubits in germanium (Ge) have focused primarily on singly occupied quantum dots. Here, we theoretically investigate three-hole qubits in germanium and demonstrate that their performance can rival that of single-hole qubits in both strained and unstrained systems. In particular, we find that—in the widely used quasi-circular geometry—a three-hole qubit encoding can yield enhancements of the Rabi frequencies by up to 2 orders of magnitude and a large advantage in terms of quality factors.

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Phys. Rev. Applied 26, 054031– Published 10 November, 2026
  • Received 8 May 2025
  • Revised 7 July 2026
  • Accepted 9 October 2026
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