Tunable Josephson Generator for Qubit Excitation and Two‐Tone Spectroscopy
ABSTRACT We present a tunable Josephson generator that enables direct qubit excitation and two‐tone spectroscopy while reducing cryogenic wiring complexity and thermal load. The device consists of a current‐biased Josephson junction integrated with a superconducting spiral resonator, forming a microwave source that operates at cryogenic temperatures. Unlike conventional qubit drive setups that require coaxial microwave lines from room temperature to the base stage, our system requires only a single direct current (DC) bias line from room temperature. The generated microwave signal is delivered to the qubit via a short coaxial line between the 4 K and 20 mK stages, significantly reducing wiring complexity, thermal load in the cryostat and leveraging unused volume at the 4 K stage. We demonstrate continuous‐wave excitation of a superconducting qubit and perform tunable two‐tone spectroscopy using the Josephson generator as the drive source, resolving qubit spectra with performance comparable to a standard microwave source. Our generator is characterized by low phase noise and can be phase‐locked to an external reference for enhanced stability. Operating at 4 K temperature, this self‐contained source offers a low‐noise, space‐efficient solution for qubit control and spectroscopy, paving the way for scalable cryogenic quantum control architectures.
Authors
- A. D. Belanovsky (ORCID: https://orcid.org/0000-0002-5565-7187)
- Nataliya Maleeva (ORCID: https://orcid.org/0000-0002-1142-2626)
- M. Yu. Kupriyanov (ORCID: https://orcid.org/0000-0003-1204-9664)
- Rustam D. Yusupov (ORCID: https://orcid.org/0000-0001-8544-5954)
- V. P. Koshelets (ORCID: https://orcid.org/0000-0002-1563-1257)
- Dmitry S. Yakovlev (ORCID: https://orcid.org/0000-0002-6894-2139)
- G. S. Khismatullin (ORCID: https://orcid.org/0009-0008-3108-7117)
- Ivan A. Nazhestkin (ORCID: https://orcid.org/0000-0003-2482-7742)
- V. V. Ryazanov (ORCID: https://orcid.org/0000-0002-6895-5829)
- A. S. Ionin (ORCID: https://orcid.org/0009-0004-0249-1234)
- N. V. Klenov (ORCID: https://orcid.org/0000-0001-6265-3670)
- M. Yu. Fominskii
- I. I. Soloviev (ORCID: https://orcid.org/0000-0001-9735-2720)
- V. A. Vozhakov
- Georgy I. Gubochkin (ORCID: https://orcid.org/0009-0005-1416-8546)
- P. A. Gladilovich (ORCID: https://orcid.org/0009-0005-5386-0420)
- M. M. Khrenov (ORCID: https://orcid.org/0009-0009-3538-5565)
- L. V. Filippenko
Institutions
- National University of Science and Technology (RU)
- Centre National de la Recherche Scientifique (FR)
- Lomonosov Moscow State University (RU)
- National University of Science and Technology (ZW)
- Sorbonne Université (FR)
- Laboratoire de Physique et d’Étude des Matériaux (FR)
- Russian Quantum Center (RU)
- Centre of Advanced Studies (RU)
- Kotelnikov Institute of Radioengineering and Electronics of the Russian Academy of Sciences (RU)
Publication Details
- Journal
- Advanced Quantum Technologies
- Published
- 2025-12-01
- DOI
- https://doi.org/10.1002/qute.202500659
- Primary Topic
- Quantum Information and Cryptography
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- Agence Nationale de la Recherche
- Russian Science Foundation
- National University of Science and Technology