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A superconductor free of quasiparticles for seconds

Nature Physics volume 18, pages 145–148 (2022)Cite this article

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Abstract

Superconducting devices, based on the Cooper pairing of electrons, play an important role in existing and emergent technologies, ranging from radiation detectors1,2 to quantum computers3. Their performance is limited by spurious quasiparticle excitations formed from broken Cooper pairs4,5,6,7,8,9,10,11,12. Efforts to achieve ultra-low quasiparticle densities have reached time-averaged numbers of excitations on the order of one in state-of-the-art devices2,12,13,14,15. However, the dynamics of the quasiparticle population as well as the timescales for adding and removing individual excitations remain largely unexplored. Here, we experimentally demonstrate a superconductor completely free of quasiparticles for periods lasting up to seconds. We monitor the quasiparticle number on a mesoscopic superconductor in real time by measuring the charge tunnelling to a normal metal contact. Quiet, excitation-free periods are interrupted by random-in-time Cooper pair breaking events, followed by a burst of charge tunnelling within a millisecond. Our results demonstrate the possibility of operating devices without quasiparticles with potentially improved performance. In addition, our experiment probes the origins of nonequilibrium quasiparticles in our device. The decay of the Cooper pair breaking rate over several weeks following the initial cooldown rules out processes arising from cosmic or long-lived radioactive sources16,17,18,19.

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Fig. 1: Real-time monitoring of the number of quasiparticles on a superconducting island via charge tunnelling.
Fig. 2: Statistics of Cooper pair breaking events.
Fig. 3: Dynamics of quasiparticle relaxation within a burst.
Fig. 4: Decay of burst rate over time.

Data availability

Data for figures that support the manuscript are available at https://doi.org/10.5281/zenodo.5574415. All other data that support the findings of this study are available from the corresponding author upon reasonable request.

References

  1. Day, P. K., LeDuc, H. G., Mazin, B. A., Vayonakis, A. & Zmuidzinas, J. A broadband superconducting detector suitable for use in large arrays. Nature 425, 817 (2003).

    Article  ADS  Google Scholar 

  2. Echternach, P. M., Pepper, B. J., Reck, T. & Bradford, C. M. Single photon detection of 1.5 THz radiation with the quantum capacitance detector. Nat. Astron. 2, 90 (2018).

    Article  ADS  Google Scholar 

  3. Kjaergaard, M. et al. Superconducting qubits: current state of play. Annu. Rev. Condens. Matter Phys. 11, 369 (2020).

    Article  Google Scholar 

  4. Aumentado, J., Keller, M. W., Martinis, J. M. & Devoret, M. H. Nonequilibrium quasiparticles and 2e periodicity in single-Cooper-pair transistors. Phys. Rev. Lett. 92, 066802 (2004).

    Article  ADS  Google Scholar 

  5. Shaw, M. D., Lutchyn, R. M., Delsing, P. & Echternach, P. M. Kinetics of nonequilibrium quasiparticle tunneling in superconducting charge qubits. Phys. Rev. B 78, 024503 (2008).

    Article  ADS  Google Scholar 

  6. de Visser, P. J. et al. Number fluctuations of sparse quasiparticles in a superconductor. Phys. Rev. Lett. 106, 167004 (2011).

    Article  ADS  Google Scholar 

  7. Martinis, J. M., Ansmann, M. & Aumentado, J. Energy decay in superconducting Josephson-junction qubits from nonequilibrium quasiparticle excitations. Phys. Rev. Lett. 103, 097002 (2009).

    Article  ADS  Google Scholar 

  8. Catelani, G. et al. Quasiparticle relaxation of superconducting qubits in the presence of flux. Phys. Rev. Lett. 106, 077002 (2011).

    Article  ADS  Google Scholar 

  9. Pop, I. M. et al. Coherent suppression of electromagnetic dissipation due to superconducting quasiparticles. Nature 508, 369 (2014).

    Article  ADS  Google Scholar 

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

    Article  ADS  Google Scholar 

  11. Patel, U., Pechenezhskiy, I. V., Plourde, B. L. T., Vavilov, M. G. & McDermott, R. Phonon-mediated quasiparticle poisoning of superconducting microwave resonators. Phys. Rev. B 96, 220501(R) (2017).

    Article  ADS  Google Scholar 

  12. Gustavsson, S. et al. Suppressing relaxation in superconducting qubits by quasiparticle pumping. Science 354, 1573 (2016).

    Article  ADS  Google Scholar 

  13. Ferguson, A. J. Quasiparticle cooling of a single Cooper pair transistor. Appl. Phys. Lett. 93, 052501 (2008).

    Article  ADS  Google Scholar 

  14. Higginbotham, A. P. et al. Parity lifetime of bound states in a proximitized semiconductor nanowire. Nat. Phys. 11, 1017 (2015).

    Article  Google Scholar 

  15. Vool, U. et al. Non-Poissonian quantum jumps of a fluxonium qubit due to quasiparticle excitations. Phys. Rev. Lett. 113, 247001 (2014).

    Article  ADS  Google Scholar 

  16. Vepsäläinen, A. et al. Impact of ionizing radiation on superconducting qubit coherence. Nature 584, 551 (2020).

    Article  ADS  Google Scholar 

  17. Cardani, L. et al. Reducing the impact of radioactivity on quantum circuits in a deep-underground facility. Nat. Commun. 12, 2733 (2021).

    Article  ADS  Google Scholar 

  18. Wilen, C. D. et al. Correlated charge noise and relaxation errors in superconducting qubits. Nature 594, 369 (2021).

    Article  ADS  Google Scholar 

  19. Martinis, J. M. Saving superconducting quantum processors from qubit decay and correlated errors generated by gamma and cosmic rays. npj Quantum Inf. 7, 90 (2021).

    Article  ADS  Google Scholar 

  20. Wilson, C. M., Frunzio, L. & Prober, D. E. Time-resolved measurements of thermodynamic fluctuations of the particle number in a nondegenerate Fermi gas. Phys. Rev. Lett. 87, 067004 (2001).

    Article  ADS  Google Scholar 

  21. Lambert, N. J. et al. Experimental observation of the breaking and recombination of single Cooper pairs. Phys. Rev. B 90, 140503 (2014).

    Article  ADS  Google Scholar 

  22. Serniak, K. et al. Direct dispersive monitoring of charge parity in offset-charge-sensitive transmons. Phys. Rev. Appl. 12, 014052 (2019).

    Article  ADS  Google Scholar 

  23. Van Woerkom, D. J., Geresdi, A. & Kouwenhoven, L. P. One minute parity lifetime of a NbTiN Cooper-pair transistor. Nat. Phys. 11, 547 (2015).

    Article  Google Scholar 

  24. Hays, M. et al. Direct microwave measurement of Andreev-bound-state dynamics in a semiconductor-nanowire Josephson junction. Phys. Rev. Lett. 121, 047001 (2018).

    Article  ADS  Google Scholar 

  25. Karzig, T., Cole, W. S. & Pikulin, D. I. Quasiparticle poisoning of Majorana qubits. Phys. Rev. Lett. 126, 057702 (2021).

    Article  ADS  MathSciNet  Google Scholar 

  26. Barends, R. et al. Minimizing quasiparticle generation from stray infrared light in superconducting quantum circuits. Appl. Phys. Lett. 99, 113507 (2011).

    Article  ADS  Google Scholar 

  27. Saira, O.-P., Kemppinen, A., Maisi, V. F. & Pekola, J. P. Vanishing quasiparticle density in a hybrid Al/Cu/Al single-electron transistor. Phys. Rev. B 85, 012504 (2012).

    Article  ADS  Google Scholar 

  28. Maisi, V. F. et al. Excitation of single quasiparticles in a small superconducting Al island connected to normal-metal leads by tunnel junctions. Phys. Rev. Lett. 111, 147001 (2013).

    Article  ADS  Google Scholar 

  29. Pobell, F. Matter and Methods at Low Temperatures 3rd edn (Springer-Verlag, 2007).

  30. Pekola, J. P. et al. Environment-assisted tunneling as an origin of the Dynes density of states. Phys. Rev. Lett. 105, 026803 (2010).

    Article  ADS  Google Scholar 

  31. Koski, J. V., Peltonen, J. T., Meschke, M. & Pekola, J. P. Laterally proximized aluminum tunnel junctions. Appl. Phys. Lett. 98, 203501 (2011).

    Article  ADS  Google Scholar 

  32. Zorin, A. B. The thermocoax cable as the microwave frequency filter for single electron circuits. Rev. Sci. Instrum. 66, 4296 (1995).

    Article  ADS  Google Scholar 

  33. Schoelkopf, R. J., Wahlgren, P., Kozhevnikov, A. A., Delsing, P. & Prober, D. E. The radio-frequency single-electron transistor (RF-SET): a fast and ultrasensitive electrometer. Science 280, 1238 (1998).

    Article  ADS  Google Scholar 

  34. Simbierowicz, S. et al. A flux-driven Josephson parametric amplifier for sub-GHz frequencies fabricated with side-wall passivated spacer junction technology. Superconductor Sci. Technol. 31, 105001 (2018).

    Article  ADS  Google Scholar 

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Acknowledgements

The authors thank O. Maillet for useful discussions, J. Ala-Heikkilä for support with shielding solutions and J. Lehtinen and M. Prunnila from VTT Technical Research Center of Finland Ltd., who were also involved in the JPA development. This work was performed as part of the Academy of Finland Centre of Excellence program (projects 312057, 312059 and 312294). We acknowledge the provision of facilities and technical support by Aalto University at OtaNano - Micronova Nanofabrication Centre and OtaNano - Low Temperature Laboratory. E.T.M. and J.P.P. acknowledge financial support from Microsoft. V.V. acknowledges financial support from the Academy of Finland through grant no. 321700. P.S. and V.F.M. acknowledge financial support from the Swedish National Science Foundation, and V.F.M. acknowledges financial support from the QuantERA project ‘2D hybrid materials as a platform for topological quantum computing’ and NanoLund.

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Author notes

  1. E. T. Mannila

    Present address: VTT, Espoo, Finland

  2. S. Simbierowicz

    Present address: Bluefors Oy, Helsinki, Finland

  3. J. Hassel

    Present address: IQM, Espoo, Finland

Authors and Affiliations

  1. QTF Centre of Excellence, Department of Applied Physics, Aalto University, Helsinki, Finland

    E. T. Mannila, J. T. Peltonen & J. P. Pekola

  2. Physics Department and NanoLund, Lund University, Lund, Sweden

    P. Samuelsson & V. F. Maisi

  3. VTT Technical Research Centre of Finland Ltd, QTF Centre of Excellence, VTT, Espoo, Finland

    S. Simbierowicz, V. Vesterinen, L. Grönberg & J. Hassel

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  1. E. T. Mannila
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Contributions

E.T.M., P.S., V.F.M. and J.P.P. conceived the experiment and model and interpreted the results. E.T.M. fabricated the sample and performed the experiment with support from J.T.P., and E.T.M. analysed the data. P.S. performed the theoretical modelling. S.S., V.V., L.G. and J.H. provided the Josephson parametric amplifier. E.T.M. and J.T.P. integrated the Josephson parametric amplifier into the set-up with assistance from S.S. and V.V. The manuscript was written by E.T.M. and P.S. with input from all coauthors.

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Correspondence to E. T. Mannila.

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Supplementary information

Supplementary Notes 1–8 and Figs. S1–S13.

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Mannila, E.T., Samuelsson, P., Simbierowicz, S. et al. A superconductor free of quasiparticles for seconds. Nat. Phys. 18, 145–148 (2022). https://doi.org/10.1038/s41567-021-01433-7

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