Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

A thermal-noise-resilient microwave quantum network up to 4 K

Nature Electronics volume 9, pages 279–286 (2026) Cite this article

Subjects

Abstract

Quantum communication at microwave frequencies is of use in the development of scalable quantum networks. However, such networks are fundamentally constrained by the susceptibility of microwave photons to thermal noise. Here we report a thermal-noise-resilient microwave quantum network with coherent coupling between two superconducting qubits through a 4-K-thermalized niobium–titanium transmission line. By overcoupling the communication channel to a cold load at 10 mK, we suppress the effective thermal occupancy of the channel to 0.06 photons through radiative cooling—a reduction that is 2 orders of magnitude below ambient thermal noise. We then decouple the cold load and rapidly transfer microwave quantum states through the channel while it rethermalizes. With this approach, we achieve a 58.5% process fidelity for quantum state transfer and a 52.3% Bell entanglement fidelity without correcting for readout errors, both exceeding the classical communication threshold of 1/2. We also develop a set-up with improved channel coherence at 1 K and use this to achieve a Bell entanglement fidelity of 93.6%. As a benchmark, we demonstrate that Bell’s inequality is unambiguously violated with this remote entanglement, without correcting for readout errors.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on SpringerLink
  • Instant access to the full article PDF.

USD 39.95

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Experimental set-up.
The alternative text for this image may have been generated using AI.
Fig. 2: Tunable channel dissipation.
The alternative text for this image may have been generated using AI.
Fig. 3: Radiative cooling and rethermalization.
The alternative text for this image may have been generated using AI.
Fig. 4: Quantum state transfer and remote entanglement at 4 K.
The alternative text for this image may have been generated using AI.
Fig. 5: Quantum state transfer, entanglement generation and verification at 1 K.
The alternative text for this image may have been generated using AI.

Similar content being viewed by others

Data availability

The data that support the plots within this article and other findings of this study are available from the corresponding authors upon request.

References

  1. Krantz, P. et al. A quantum engineer’s guide to superconducting qubits. Appl. Phys. Rev. 6, 021318 (2019).

    Article  Google Scholar 

  2. Blais, A., Grimsmo, A. L., Girvin, S. M. & Wallraff, A. Circuit quantum electrodynamics. Rev. Mod. Phys. 93, 025005 (2021).

    Article  MathSciNet  Google Scholar 

  3. Google Quantum AI and Collaborators et al. Quantum error correction below the surface code threshold. Nature 638, 920–926 (2025).

    Article  Google Scholar 

  4. Bravyi, S., Dial, O., Gambetta, J. M., Gil, D. & Nazario, Z. The future of quantum computing with superconducting qubits. J. Appl. Phys. 132, 160902 (2022).

    Article  Google Scholar 

  5. Kurpiers, P. et al. Deterministic quantum state transfer and remote entanglement using microwave photons. Nature 558, 264–267 (2018).

    Article  Google Scholar 

  6. Axline, C. J. et al. On-demand quantum state transfer and entanglement between remote microwave cavity memories. Nat. Phys. 14, 705–710 (2018).

    Article  Google Scholar 

  7. Campagne-Ibarcq, P. et al. Deterministic remote entanglement of superconducting circuits through microwave two-photon transitions. Phys. Rev. Lett. 120, 200501 (2018).

    Article  Google Scholar 

  8. Leung, N. et al. Deterministic bidirectional communication and remote entanglement generation between superconducting qubits. NPJ Quantum Inf. 5, 18 (2019).

    Article  Google Scholar 

  9. Magnard, P. et al. Microwave quantum link between superconducting circuits housed in spatially separated cryogenic systems. Phys. Rev. Lett. 125, 260502 (2020).

    Article  Google Scholar 

  10. Storz, S. et al. Loophole-free bell inequality violation with superconducting circuits. Nature 617, 265–270 (2023).

    Article  Google Scholar 

  11. Qiu, J. et al. Deterministic quantum state and gate teleportation between distant superconducting chips. Sci. Bull. 70, 351–358 (2025).

    Article  Google Scholar 

  12. Zhong, Y. et al. Deterministic multi-qubit entanglement in a quantum network. Nature 590, 571–575 (2021).

    Article  Google Scholar 

  13. Burkhart, L. D. et al. Error-detected state transfer and entanglement in a superconducting quantum network. PRX Quantum 2, 030321 (2021).

    Article  Google Scholar 

  14. Niu, J. et al. Low-loss interconnects for modular superconducting quantum processors. Nat. Electron. 6, 235–241 (2023).

    Article  Google Scholar 

  15. Kannan, B. et al. On-demand directional microwave photon emission using waveguide quantum electrodynamics. Nat. Phys. 19, 394–400 (2023).

    Article  Google Scholar 

  16. Mollenhauer, M., Irfan, A., Cao, X., Mandal, S. & Pfaff, W. A high-efficiency elementary network of interchangeable superconducting qubit devices. Nat. Electron. 8, 610–619 (2025).

    Article  Google Scholar 

  17. Song, J. et al. Realization of high-fidelity perfect entanglers between remote superconducting quantum processors. Phys. Rev. Lett. 135, 050603 (2025).

    Article  Google Scholar 

  18. Almanakly, A. et al. Deterministic remote entanglement using a chiral quantum interconnect. Nat. Phys. 21, 825–830 (2025).

    Article  Google Scholar 

  19. Deng, X. et al. Long-range zz interaction via resonator-induced phase in superconducting qubits. Phys. Rev. Lett. 134, 020801 (2025).

    Article  Google Scholar 

  20. Habraken, S. J. M., Stannigel, K., Lukin, M. D., Zoller, P. & Rabl, P. Continuous mode cooling and phonon routers for phononic quantum networks. New J. Phys. 14, 115004 (2012).

    Article  MathSciNet  Google Scholar 

  21. Xiang, Z.-L., Zhang, M., Jiang, L. & Rabl, P. Intracity quantum communication via thermal microwave networks. Phys. Rev. X 7, 11035 (2017).

    Google Scholar 

  22. Vermersch, B., Guimond, P.-O., Pichler, H. & Zoller, P. Quantum state transfer via noisy photonic and phononic waveguides. Phys. Rev. Lett. 118, 133601 (2017).

    Article  Google Scholar 

  23. Yam, W. K. et al. Cryogenic microwave link for quantum local area networks. NPJ Quantum Inf. 11, 87 (2025).

    Article  Google Scholar 

  24. Albanese, B. et al. Radiative cooling of a spin ensemble. Nat. Phys. 16, 751–755 (2020).

    Article  Google Scholar 

  25. Xu, M. et al. Radiative cooling of a superconducting resonator. Phys. Rev. Lett. 124, 33602 (2020).

    Article  Google Scholar 

  26. Wang, Z. et al. Quantum microwave radiometry with a superconducting qubit. Phys. Rev. Lett. 126, 180501 (2021).

    Article  Google Scholar 

  27. Xiang, Z.-L., Ashhab, S., You, J. Q. & Nori, F. Hybrid quantum circuits: superconducting circuits interacting with other quantum systems. Rev. Mod. Phys. 85, 623–653 (2013).

    Article  Google Scholar 

  28. Clerk, A. A., Lehnert, K. W., Bertet, P., Petta, J. R. & Nakamura, Y. Hybrid quantum systems with circuit quantum electrodynamics. Nat. Phys. 16, 257–267 (2020).

    Article  Google Scholar 

  29. Huang, G., Beccari, A., Engelsen, N. J. & Kippenberg, T. J. Room-temperature quantum optomechanics using an ultralow noise cavity. Nature 626, 512–516 (2024).

    Article  Google Scholar 

  30. Koch, J. et al. Charge-insensitive qubit design derived from the cooper pair box. Phys. Rev. A 76, 042319 (2007).

    Article  Google Scholar 

  31. Chen, Y. et al. Qubit architecture with high coherence and fast tunable coupling. Phys. Rev. Lett. 113, 220502 (2014).

    Article  Google Scholar 

  32. Jeffrey, E. et al. Fast accurate state measurement with superconducting qubits. Phys. Rev. Lett. 112, 190504 (2014).

    Article  Google Scholar 

  33. Chang, H.-S. et al. A fast and large bandwidth superconducting variable coupler. Appl. Phys. Lett. 117, 244001 (2020).

    Article  Google Scholar 

  34. Jin, X. Y. et al. Thermal and residual excited-state population in a 3D transmon qubit. Phys. Rev. Lett. 114, 240501 (2015).

    Article  Google Scholar 

  35. Scigliuzzo, M. et al. Primary thermometry of propagating microwaves in the quantum regime. Phys. Rev. X 10, 41054 (2020).

    Google Scholar 

  36. Lvov, D. S., Lemziakov, S. A., Ankerhold, E., Peltonen, J. T. & Pekola, J. P. Thermometry based on a superconducting qubit. Phys. Rev. Appl. 23, 54079 (2025).

    Article  Google Scholar 

  37. Wootters, W. K. Entanglement of formation of an arbitrary state of two qubits. Phys. Rev. Lett. 80, 2245–2248 (1998).

    Article  Google Scholar 

  38. Ramette, J., Sinclair, J., Breuckmann, N. P. & Vuletic, V. Fault-tolerant connection of error-corrected qubits with noisy links. NPJ Quantum Inf. 10, 58 (2024).

    Article  Google Scholar 

  39. Clauser, J. F., Horne, M. A., Shimony, A. & Holt, R. A. Proposed experiment to test local hidden-variable theories. Phys. Rev. Lett. 23, 880–884 (1969).

    Article  Google Scholar 

  40. Petit, L. et al. Universal quantum logic in hot silicon qubits. Nature 580, 355–359 (2020).

    Article  Google Scholar 

  41. Yang, C. H. et al. Operation of a silicon quantum processor unit cell above one kelvin. Nature 580, 350–354 (2020).

    Article  Google Scholar 

  42. Camenzind, L. C. et al. A hole spin qubit in a fin field-effect transistor above 4 kelvin. Nat. Electron. 5, 178–183 (2022).

    Article  Google Scholar 

  43. Huang, J. Y. et al. High-fidelity spin qubit operation and algorithmic initialization above 1 K. Nature 627, 772–777 (2024).

    Article  Google Scholar 

  44. Dijkema, J. et al. Cavity-mediated iSWAP oscillations between distant spins. Nat. Phys. 21, 168–174 (2025).

    Article  Google Scholar 

  45. Aspelmeyer, M., Kippenberg, T. J. & Marquardt, F. Cavity optomechanics. Rev. Mod. Phys. 86, 1391–1452 (2014).

    Article  Google Scholar 

  46. Mirhosseini, M., Sipahigil, A., Kalaee, M. & Painter, O. Superconducting qubit to optical photon transduction. Nature 588, 599–603 (2020).

    Article  Google Scholar 

  47. Tu, H. T. et al. High efficiency coherent microwave-to-optics conversion via off-resonant scattering. Nat. Photon. 16, 291–296 (2022).

    Article  Google Scholar 

  48. Kumar, A. et al. Quantum-enabled millimetre wave to optical transduction using neutral atoms. Nature 615, 614–619 (2023).

    Article  Google Scholar 

  49. Sahu, R. et al. Entangling microwaves with light. Science 380, 718–721 (2023).

    Article  MathSciNet  Google Scholar 

  50. Jiang, W. et al. Optically heralded microwave photon addition. Nat. Phys. 19, 1423–1428 (2023).

    Article  Google Scholar 

  51. Meesala, S. et al. Quantum entanglement between optical and microwave photonic qubits. Phys. Rev. X 14, 031055 (2024).

    Google Scholar 

  52. Anferov, A., Harvey, S. P., Wan, F., Simon, J. & Schuster, D. I. Superconducting qubits above 20 GHz operating over 200 mK. PRX Quantum 5, 30347 (2024).

    Article  Google Scholar 

  53. Anferov, A., Wan, F., Harvey, S. P., Simon, J. & Schuster, D. I. Millimeter-wave superconducting qubit. PRX Quantum 6, 020336 (2025).

    Article  Google Scholar 

  54. Sun, L. et al. Measurements of quasiparticle tunneling dynamics in a band-gap-engineered transmon qubit. Phys. Rev. Lett. 108, 230509 (2012).

    Article  Google Scholar 

  55. Wang, C. et al. Measurement and control of quasiparticle dynamics in a superconducting qubit. Nat. Commun. 5, 5836 (2014).

    Article  Google Scholar 

  56. Stas, P.-J. et al. Robust multi-qubit quantum network node with integrated error detection. Science 378, 557–560 (2022).

    Article  Google Scholar 

  57. Grebel, J. et al. Bidirectional multiphoton communication between remote superconducting nodes. Phys. Rev. Lett. 132, 47001 (2024).

    Article  Google Scholar 

  58. Valenzuela, S. O. et al. Microwave-induced cooling of a superconducting qubit. Science 314, 1589–1592 (2006).

    Article  Google Scholar 

  59. Gely, M. F. et al. Observation and stabilization of photonic fock states in a hot radio-frequency resonator. Science 363, 1072–1075 (2019).

    Article  Google Scholar 

  60. Aamir, M. A. et al. Thermally driven quantum refrigerator autonomously resets a superconducting qubit. Nat. Phys. 21, 318–323 (2025).

    Article  Google Scholar 

  61. Steffen, M. et al. Measurement of the entanglement of two superconducting qubits via state tomography. Science 313, 1423–1425 (2006).

    Article  MathSciNet  Google Scholar 

  62. Diamond, S. & Boyd, S. CVXPY: a Python-embedded modeling language for convex optimization. J. Mach. Learn. Res. 17, 2909–2913 (2016).

    MathSciNet  Google Scholar 

  63. Neeley, M. et al. Process tomography of quantum memory in a Josephson-phase qubit coupled to a two-level state. Nat. Phys. 4, 523–526 (2008).

    Article  Google Scholar 

  64. Massar, S. & Popescu, S. Optimal extraction of information from finite quantum ensembles. Phys. Rev. Lett. 74, 1259–1263 (1995).

    Article  MathSciNet  Google Scholar 

  65. Horodecki, M., Horodecki, P. & Horodecki, R. General teleportation channel, singlet fraction, and quasidistillation. Phys. Rev. A 60, 1888–1898 (1999).

    Article  MathSciNet  Google Scholar 

  66. Steffen, L. et al. Deterministic quantum teleportation with feed-forward in a solid state system. Nature 500, 319–322 (2013).

    Article  Google Scholar 

Download references

Acknowledgements

We thank J.-W. Pan and L. Duan for insightful discussions, and thank H. Jin for providing thermometers used in this experiment. This work was supported by the Science, Technology and Innovation Commission of Shenzhen Municipality (grant no. KQTD20210811090049034), the National Natural Science Foundation of China (grant nos 12174178, 12374474 and 12504582), the Innovation Program for Quantum Science and Technology (grant no. 2021ZD0301703), Guangdong Basic and Applied Basic Research Foundation (grant nos 2024A1515011714 and 2022A1515110615) and the Department of Science and Technology of Guangdong Province (grant no. 2020B0303050001).

Author information

Author notes

  1. These authors contributed equally: Jiawei Qiu, Zihao Zhang.

Authors and Affiliations

  1. International Quantum Academy, Shenzhen, China

    Jiawei Qiu, Zihao Zhang, Zilin Wang, Libo Zhang, Yuxuan Zhou, Xuandong Sun, Jiawei Zhang, Xiayu Linpeng, Song Liu, Jingjing Niu, Youpeng Zhong & Dapeng Yu

  2. Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, China

    Jiawei Qiu, Zihao Zhang, Libo Zhang, Xuandong Sun, Jiawei Zhang & Song Liu

  3. Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, China

    Jiawei Qiu, Zihao Zhang, Libo Zhang, Xuandong Sun, Jiawei Zhang & Song Liu

  4. School of Physics, Ningxia University, Yinchuan, China

    Zilin Wang

  5. Shenzhen Branch, Hefei National Laboratory, Shenzhen, China

    Song Liu, Jingjing Niu, Youpeng Zhong & Dapeng Yu

Authors
  1. Jiawei Qiu
    View author publications

    Search author on:PubMed Google Scholar

  2. Zihao Zhang
    View author publications

    Search author on:PubMed Google Scholar

  3. Zilin Wang
    View author publications

    Search author on:PubMed Google Scholar

  4. Libo Zhang
    View author publications

    Search author on:PubMed Google Scholar

  5. Yuxuan Zhou
    View author publications

    Search author on:PubMed Google Scholar

  6. Xuandong Sun
    View author publications

    Search author on:PubMed Google Scholar

  7. Jiawei Zhang
    View author publications

    Search author on:PubMed Google Scholar

  8. Xiayu Linpeng
    View author publications

    Search author on:PubMed Google Scholar

  9. Song Liu
    View author publications

    Search author on:PubMed Google Scholar

  10. Jingjing Niu
    View author publications

    Search author on:PubMed Google Scholar

  11. Youpeng Zhong
    View author publications

    Search author on:PubMed Google Scholar

  12. Dapeng Yu
    View author publications

    Search author on:PubMed Google Scholar

Contributions

Y.Z. conceived the experiment and supervised the project. J.Q. designed and fabricated the devices, with assistance from L.Z. J.Q. and Z.Z. performed the measurements and analysed the data, guided by J.N. All authors contributed to discussions and production of the paper.

Corresponding authors

Correspondence to Jingjing Niu, Youpeng Zhong or Dapeng Yu.

Ethics declarations

Competing interests

The authors declare no competing interests.

Peer review

Peer review information

Nature Electronics thanks Blake Johnson and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data

Extended Data Fig. 1 Photograph of the experimental setup.

a, Photograph of the setup inside a dilution refrigerator. b, Zoomed in photograph of the heater and thermometer anchored near the top of the cable. c, Zoomed in photograph of Alice inside a magnetic shield. Bob is positioned behind it.

Extended Data Fig. 2 Reconstructed density matrices transferred through Thot = 4 K.

a-d, These density matrices are measured on QB used to reconstruct the process matrix χ with the initial states \(| 0\rangle\), \(| 0\rangle -i| 1\rangle\), \(| 0\rangle +| 1\rangle\), \(| 1\rangle\) prepared on QA. The left and right parts are real and imaginary components of the density matrix in each panel. The corresponding fidelities (\({{\mathcal{F}}}_{\rho }\)) are presented for cases without (purple bars) and with (orange frames) SPAM error correction.

Supplementary information

Supplementary Information (download PDF )

Supplementary information with 25 pages, 13 figures and 2 tables.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Qiu, J., Zhang, Z., Wang, Z. et al. A thermal-noise-resilient microwave quantum network up to 4 K. Nat Electron 9, 279–286 (2026). https://doi.org/10.1038/s41928-026-01581-9

Download citation

  • Received:

  • Accepted:

  • Published:

  • Version of record:

  • Issue date:

  • DOI: https://doi.org/10.1038/s41928-026-01581-9

This article is cited by

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing