Cryogenic microwave link for quantum local area networks

W. K. Yam; M. Renger; S. Gandorfer; F. Fesquet; M. Handschuh; K. E. Honasoge; F. Kronowetter; Y. Nojiri; M. Partanen; M. Pfeiffer; H. van der Vliet; A. J. Matthews; J. Govenius; R. N. Jabdaraghi; M. Prunnila; A. Marx; F. Deppe; R. Gross; K. G. Fedorov

doi:10.1038/s41534-025-01046-5

Cryogenic microwave link for quantum local area networks

W. K. Yam^*, M. Renger, S. Gandorfer, F. Fesquet, M. Handschuh, K. E. Honasoge, F. Kronowetter, Y. Nojiri, M. Partanen, M. Pfeiffer, H. van der Vliet, A. J. Matthews, J. Govenius, R. N. Jabdaraghi, M. Prunnila, A. Marx, F. Deppe, R. Gross^*, K. G. Fedorov^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › Scientific › peer-review

1 Citation (Scopus)

Abstract

Scalable quantum information processing with superconducting circuits is expected to advance from individual processors located in single dilution refrigerators to more powerful distributed quantum computing systems. The realization of hardware platforms for quantum local area networks (QLANs) compatible with superconducting technology is of high importance in order to achieve a practical quantum advantage. Here, we present a fundamental prototype platform for a microwave QLAN based on a cryogenic link connecting two separate dilution cryostats over a distance of 6.6 m with a base temperature of 52 mK in the center. Superconducting microwave coaxial cables are employed to form a quantum communication channel between the distributed network nodes. We demonstrate the continuous-variable entanglement distribution between the remote dilution refrigerators in the form of two-mode squeezed microwave states, reaching squeezing of 2.10 ± 0.02 dB and negativity of 0.501 ± 0.011. Furthermore, we show that quantum entanglement is preserved at channel center temperatures up to 1 K, paving the way towards microwave quantum communication at elevated temperatures. Consequently, such a QLAN system can form the backbone for future distributed quantum computing with superconducting circuits.

Original language	English
Article number	87
Journal	NPJ Quantum Information
Volume	11
DOIs	https://doi.org/10.1038/s41534-025-01046-5
Publication status	Published - May 2025
MoE publication type	A1 Journal article-refereed

Funding

We acknowledge support by the German Research Foundation via Germany`s Excellence Strategy (EXC-2111-390814868), the EU Quantum Flagship project QMiCS (Grant No. 820505), the German Federal Ministry of Education and Research via the project QUARATE (Grant No. 13N15380). We acknowledge funding from European Union's Horizon 2020 research and innovation programme under grant agreement No. 824109 European Microkelvin Platform (EMP), the Academy of Finland through the QTF Centre of Excellence project No. 336817, Business Finland through QuTI-project (No. 128291). We also acknowledge Technology Industries of Finland Centennial Foundation for funding. This research is part of the Munich Quantum Valley, which is supported by the Bavarian state government with funds from the Hightech Agenda Bayern Plus.

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Yam, W. K., Renger, M., Gandorfer, S., Fesquet, F., Handschuh, M., Honasoge, K. E., Kronowetter, F., Nojiri, Y., Partanen, M., Pfeiffer, M., van der Vliet, H., Matthews, A. J., Govenius, J., Jabdaraghi, R. N., Prunnila, M., Marx, A., Deppe, F., Gross, R., & Fedorov, K. G. (2025). Cryogenic microwave link for quantum local area networks. NPJ Quantum Information, 11, Article 87. https://doi.org/10.1038/s41534-025-01046-5

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title = "Cryogenic microwave link for quantum local area networks",

abstract = "Scalable quantum information processing with superconducting circuits is expected to advance from individual processors located in single dilution refrigerators to more powerful distributed quantum computing systems. The realization of hardware platforms for quantum local area networks (QLANs) compatible with superconducting technology is of high importance in order to achieve a practical quantum advantage. Here, we present a fundamental prototype platform for a microwave QLAN based on a cryogenic link connecting two separate dilution cryostats over a distance of 6.6 m with a base temperature of 52 mK in the center. Superconducting microwave coaxial cables are employed to form a quantum communication channel between the distributed network nodes. We demonstrate the continuous-variable entanglement distribution between the remote dilution refrigerators in the form of two-mode squeezed microwave states, reaching squeezing of 2.10 ± 0.02 dB and negativity of 0.501 ± 0.011. Furthermore, we show that quantum entanglement is preserved at channel center temperatures up to 1 K, paving the way towards microwave quantum communication at elevated temperatures. Consequently, such a QLAN system can form the backbone for future distributed quantum computing with superconducting circuits.",

author = "Yam, {W. K.} and M. Renger and S. Gandorfer and F. Fesquet and M. Handschuh and Honasoge, {K. E.} and F. Kronowetter and Y. Nojiri and M. Partanen and M. Pfeiffer and {van der Vliet}, H. and Matthews, {A. J.} and J. Govenius and Jabdaraghi, {R. N.} and M. Prunnila and A. Marx and F. Deppe and R. Gross and Fedorov, {K. G.}",

year = "2025",

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doi = "10.1038/s41534-025-01046-5",

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Yam, WK, Renger, M, Gandorfer, S, Fesquet, F, Handschuh, M, Honasoge, KE, Kronowetter, F, Nojiri, Y, Partanen, M, Pfeiffer, M, van der Vliet, H, Matthews, AJ, Govenius, J, Jabdaraghi, RN, Prunnila, M, Marx, A, Deppe, F, Gross, R & Fedorov, KG 2025, 'Cryogenic microwave link for quantum local area networks', NPJ Quantum Information, vol. 11, 87. https://doi.org/10.1038/s41534-025-01046-5

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AU - Yam, W. K.

AU - Renger, M.

AU - Gandorfer, S.

AU - Fesquet, F.

AU - Handschuh, M.

AU - Honasoge, K. E.

AU - Kronowetter, F.

AU - Nojiri, Y.

AU - Partanen, M.

AU - Pfeiffer, M.

AU - van der Vliet, H.

AU - Matthews, A. J.

AU - Govenius, J.

AU - Jabdaraghi, R. N.

AU - Prunnila, M.

AU - Marx, A.

AU - Deppe, F.

AU - Gross, R.

AU - Fedorov, K. G.

PY - 2025/5

Y1 - 2025/5

N2 - Scalable quantum information processing with superconducting circuits is expected to advance from individual processors located in single dilution refrigerators to more powerful distributed quantum computing systems. The realization of hardware platforms for quantum local area networks (QLANs) compatible with superconducting technology is of high importance in order to achieve a practical quantum advantage. Here, we present a fundamental prototype platform for a microwave QLAN based on a cryogenic link connecting two separate dilution cryostats over a distance of 6.6 m with a base temperature of 52 mK in the center. Superconducting microwave coaxial cables are employed to form a quantum communication channel between the distributed network nodes. We demonstrate the continuous-variable entanglement distribution between the remote dilution refrigerators in the form of two-mode squeezed microwave states, reaching squeezing of 2.10 ± 0.02 dB and negativity of 0.501 ± 0.011. Furthermore, we show that quantum entanglement is preserved at channel center temperatures up to 1 K, paving the way towards microwave quantum communication at elevated temperatures. Consequently, such a QLAN system can form the backbone for future distributed quantum computing with superconducting circuits.

AB - Scalable quantum information processing with superconducting circuits is expected to advance from individual processors located in single dilution refrigerators to more powerful distributed quantum computing systems. The realization of hardware platforms for quantum local area networks (QLANs) compatible with superconducting technology is of high importance in order to achieve a practical quantum advantage. Here, we present a fundamental prototype platform for a microwave QLAN based on a cryogenic link connecting two separate dilution cryostats over a distance of 6.6 m with a base temperature of 52 mK in the center. Superconducting microwave coaxial cables are employed to form a quantum communication channel between the distributed network nodes. We demonstrate the continuous-variable entanglement distribution between the remote dilution refrigerators in the form of two-mode squeezed microwave states, reaching squeezing of 2.10 ± 0.02 dB and negativity of 0.501 ± 0.011. Furthermore, we show that quantum entanglement is preserved at channel center temperatures up to 1 K, paving the way towards microwave quantum communication at elevated temperatures. Consequently, such a QLAN system can form the backbone for future distributed quantum computing with superconducting circuits.

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Cryogenic microwave link for quantum local area networks

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