Non-exponential decay of a giant artificial atom


In quantum optics, light–matter interaction has conventionally been studied using small atoms interacting with electromagnetic fields with wavelength several orders of magnitude larger than the atomic dimensions1,2. In contrast, here we experimentally demonstrate the vastly different ‘giant atom’ regime, where an artificial atom interacts with acoustic fields with wavelength several orders of magnitude smaller than the atomic dimensions. This is achieved by coupling a superconducting qubit3 to surface acoustic waves at two points with separation on the order of 100 wavelengths. This approach is comparable to controlling the radiation of an atom by attaching it to an antenna. The slow velocity of sound leads to a significant internal time-delay for the field to propagate across the giant atom, giving rise to non-Markovian dynamics4. We demonstrate the non-Markovian character of the giant atom in the frequency spectrum as well as non-exponential relaxation in the time domain.

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Fig. 1: Device layouts.
Fig. 2: Scattering properties of the giant atom.
Fig. 3: Frequency response and dynamics of the giant atom.

Data availability

The data generated and analysed in this study are available from the corresponding authors upon reasonable request.


  1. 1.

    Brune, M., Haroche, S., Lefevre, V., Raimond, J. M. & Zagury, N. Quantum nondemolition measurement of small photon numbers by Rydberg-atom phase-sensitive detection. Phys. Rev. Lett. 65, 976–979 (1990).

  2. 2.

    Raimond, J. M., Brune, M. & Haroche, S. Manipulating quantum entanglement with atoms and photons in a cavity. Rev. Mod. Phys. 73, 565–582 (2001).

  3. 3.

    Schoelkopf, R. J. & Girvin, S. M. Wiring up quantum systems. Nature 451, 664–669 (2008).

  4. 4.

    Guo, L., Grimsmo, A. L., Kockum, A. F., Pletyukhov, M. & Johansson, G. Giant acoustic atom: a single quantum system with a deterministic time delay. Phys. Rev. A 95, 053821 (2017).

  5. 5.

    Goy, P., Raimond, J. M., Gross, M. & Haroche, S. Observation of cavity-enhanced single-atom spontaneous emission. Phys. Rev. Lett. 50, 1903–1906 (1983).

  6. 6.

    Miller, R. et al. Trapped atoms in cavity QED: coupling quantized light and matter. J. Phys. B 38, S551 (2005).

  7. 7.

    Gu, X., Kockum, A., Miranowicz, A., Liu, Y. & Nori, F. Microwave photonics with superconducting quantum circuits. Phys. Rep. 718, 1–102 (2017).

  8. 8.

    Wallraff, A. et al. Strong coupling of a single photon to a superconducting qubit using circuit quantum electrodynamics. Nature 431, 162–167 (2004).

  9. 9.

    Hofheinz, M. et al. Synthesizing arbitrary quantum states in a superconducting resonator. Nature 459, 546–549 (2009).

  10. 10.

    Wang, C. et al. A Schrödinger cat living in two boxes. Science 352, 1087–1091 (2016).

  11. 11.

    Hoi, I. C. et al. Demonstration of a single-photon router in the microwave regime. Phys. Rev. Lett. 107, 073601 (2011).

  12. 12.

    Abdumalikov, A. A. et al. Electromagnetically induced transparency on a single artificial atom. Phys. Rev. Lett. 104, 193601 (2010).

  13. 13.

    Roy, D., Wilson, C. M. & Firstenberg, O. Colloquium: strongly interacting photons in one-dimensional continuum. Rev. Mod. Phys. 89, 021001 (2017).

  14. 14.

    Paik, H. et al. Observation of high coherence in Josephson junction qubits measured in a three-dimensional circuit QED architecture. Phys. Rev. Lett. 107, 240501 (2011).

  15. 15.

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

  16. 16.

    Gustafsson, M. V. et al. Propagating phonons coupled to an artificial atom. Science 346, 207–211 (2014).

  17. 17.

    Manenti, R. et al. Circuit quantum acoustodynamics with surface acoustic waves. Nat. Commun. 8, 975 (2017).

  18. 18.

    Chu, Y. et al. Quantum acoustics with superconducting qubits. Science 358, 199–202 (2017).

  19. 19.

    Moores, B. A., Sletten, L. R., Viennot, J. J. & Lehnert, K. W. Cavity quantum acoustic device in the multimode strong coupling regime. Phys. Rev. Lett. 120, 227701 (2018).

  20. 20.

    Bolgar, A. N. et al. Quantum regime of a two-dimensional phonon cavity. Phys. Rev. Lett. 120, 223603 (2018).

  21. 21.

    Noguchi, A., Yamazaki, R., Tabuchi, Y. & Nakamura, Y. Qubit-assisted transduction for a detection of surface acoustic waves near the quantum limit. Phys. Rev. Lett. 119, 180505 (2017).

  22. 22.

    Manenti, R. et al. Surface acoustic wave resonators in the quantum regime. Phys. Rev. B 93, 041411 (2016).

  23. 23.

    Satzinger, K. J. et al. Quantum control of surface acoustic wave phonons. Nature 563, 661–665 (2018).

  24. 24.

    Kockum, A. F., Delsing, P. & Johansson, G. Designing frequency-dependent relaxation rates and Lamb shifts for a giant artificial atom. Phys. Rev. A 90, 013837 (2014).

  25. 25.

    Breuer, H.-P., Laine, E.-M., Piilo, J. & Vacchini, B. Colloquium: non-Markovian dynamics in open quantum systems. Rev. Mod. Phys. 88, 021002 (2016).

  26. 26.

    Pichler, H. & Zoller, P. Photonic circuits with time delays and quantum feedback. Phys. Rev. Lett. 116, 093601 (2016).

  27. 27.

    Pichler, H., Choi, S., Zoller, P. & Lukin, M. D. Universal photonic quantum computation via time-delayed feedback. Proc. Natl Acad. Sci. USA 114, 11362–11367 (2017).

  28. 28.

    Kockum, A. F., Johansson, G. & Nori, F. Decoherence-free interaction between giant atoms in waveguide quantum electrodynamics. Phys. Rev. Lett. 120, 140404 (2018).

  29. 29.

    Aref, T. et al. in Superconducting Devices in Quantum Optics (eds Hadfield, R. H. & Johansson, G.) 217–244 (Springer International Publishing, 2016).

  30. 30.

    Astafiev, O. et al. Resonance fluorescence of a single artificial atom. Science 327, 840–843 (2010).

  31. 31.

    Breuer, H.-P., Laine, E.-M. & Piilo, J. Measure for the degree of non-Markovian behavior of quantum processes in open systems. Phys. Rev. Lett. 103, 210401 (2009).

  32. 32.

    Reed, M. D. et al. High-fidelity readout in circuit quantum electrodynamics using the Jaynes-Cummings nonlinearity. Phys. Rev. Lett. 105, 173601 (2010).

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This work was supported by the Knut and Alice Wallenberg foundation and by the Swedish Research Council (VR). This project has also received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 642688. We acknowledge fruitful discussions with M. K. Ekström and G. Johansson.

Author information

G.A., B.S. and T.A. contributed to the design and fabrication of devices. L.G. developed the theoretical expressions for spectra and relaxation rates. G.A. and B.S. performed the measurements. All authors contributed to discussions and the interpretation of results. P.D. supervised the project, and G.A., B.S., L.G. and P.D. contributed to the writing of the manuscript.

Correspondence to Lingzhen Guo or Per Delsing.

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