Compromise-free scaling of qubit speed and coherence
Across leading qubit platforms, a common trade-off persists: increasing coherence comes at the cost of operational speed, reflecting the notion that protecting a qubit from its noisy surroundings also limits control over it. This speed-coherence dilemma limits qubit performance across various technologies. Here, we demonstrate a hole spin qubit in a Ge/Si core/shell nanowire that triples its Rabi frequency while simultaneously quadrupling its Hahn-echo coherence time, boosting the Q-factor by over an order of magnitude. This is enabled by the direct Rashba spin-orbit interaction, emerging from heavy-hole-light-hole mixing through strong confinement in two dimensions. Tuning a gate voltage causes this interaction to peak, providing maximum drive speed and a point where the qubit is optimally protected from charge noise, allowing speed and coherence to scale together. Our proof-of-concept shows that careful dot design can overcome a long-standing limitation, offering a new approach towards building high-performance, fault-tolerant qubits.
Authors
- Daniel Loss (ORCID: https://orcid.org/0000-0001-5176-3073)
- Jonas Schuff (ORCID: https://orcid.org/0000-0002-8880-2125)
- Natalia Ares (ORCID: https://orcid.org/0000-0003-2588-6322)
- Stefano Bosco (ORCID: https://orcid.org/0000-0002-4035-9654)
- Simon Svab (ORCID: https://orcid.org/0009-0004-0545-0307)
- Taras Patlatiuk
- Erik P. A. M. Bakkers (ORCID: https://orcid.org/0000-0002-8264-6862)
- Dominik M. Zumbühl (ORCID: https://orcid.org/0000-0001-5831-633X)
- Rafael S. Eggli (ORCID: https://orcid.org/0009-0007-3483-8986)
- J. Carlos Egues (ORCID: https://orcid.org/0000-0003-0856-3599)
- Leon C. Camenzind (ORCID: https://orcid.org/0000-0002-2278-1915)
- Pierre Chevalier Kwon
- Miguel J. Carballido (ORCID: https://orcid.org/0000-0001-7385-8284)
- R. Kaiser
- Ang Li (ORCID: https://orcid.org/0000-0002-9802-9359)
Institutions
- Universidade de São Paulo (BR)
- University of Basel (CH)
- Beijing University of Technology (CN)
- University of Oxford (GB)
- RIKEN (JP)
- QuTech (NL)
- Eindhoven University of Technology (NL)
- Delft University of Technology (NL)
Publication Details
- Journal
- Nature Communications
- Published
- 2025-08-15
- DOI
- https://doi.org/10.1038/s41467-025-62614-z
- Citations
- 11
- Primary Topic
- Quantum Information and Cryptography
- Type
- article
- Field-Weighted Citation Impact
- 27.29
Funders
- National Science Foundation
- Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung
- Conselho Nacional de Desenvolvimento Científico e Tecnológico
- Horizon 2020 Framework Programme
- Swiss Nanoscience Institute