Skip to main content

Thank you for visiting 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.

High-sensitivity magnetometry with a single atom in a superposition of two circular Rydberg states


Superpositions of states with macroscopically different properties, named ‘cats’ after Schrödinger’s Gedanken experiment, are extraordinarily sensitive probes of their environment. They can be used to investigate the decoherence mechanism and the quantum-to-classical transition1,2,3,4,5, as well as to realize quantum-enabled sensors6 with promising applications. We report here the creation of a ‘circular cat’, namely an atom in a superposition of two circular Rydberg states with huge opposite magnetic momenta. It is an exquisite probe of the magnetic field, able to perform a single-shot detection of a 13 nT field in only 20 μs. This single-atom cat is as sensitive as a set of 1,800 ordinary atoms, demonstrating the usefulness of Rydberg state engineering for quantum-enabled technologies.

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

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Stark manifold of the rubidium atom.
Fig. 2: Preparation sequence.
Fig. 3: Characterization of the CSS.
Fig. 4: Sensitivity to the magnetic field.

Data availability

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


  1. Greiner, M., Mandel, O., Hänsch, T. W. & Bloch, I. Collapse and revival of the matter wave field of a Bose–Einstein condensate. Nature 519, 51–54 (2002).

    Article  ADS  Google Scholar 

  2. Raimond, J.-M. & Haroche, S. Exploring the Quantum (Oxford Univ. Press, New York, 2006).

  3. Deléglise, S. et al. Reconstruction of non-classical cavity field states with snapshots of their decoherence. Nature 455, 510–514 (2008).

    Article  ADS  Google Scholar 

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

    Article  ADS  MathSciNet  Google Scholar 

  5. Johnson, K. G., Wong-Campos, J. D., Neyenhuis, B., Mizrahi, J. & MonroeUltrafast, C. Creation of large Schrödinger cat states of an atom. Nat. Commun. 8, 697 (2017).

    Article  ADS  Google Scholar 

  6. Facon, A. et al. A sensitive electrometer based on a Rydberg atom in a Schrödinger-cat state. Nature 535, 262–265 (2016).

    Article  ADS  Google Scholar 

  7. Ripka, P. Review of fluxgate sensors. Sens. Actuat. A 33, 129–141 (1992).

    Article  Google Scholar 

  8. Hämäläinen, M., Hari, R., Ilmoniemi, R. J., Knuutila, J. & Lounasmaa, O. V. Magnetoencephalography—theory, instrumentation, and applications to noninvasive studies of the working human brain. Rev. Mod. Phys. 65, 413–497 (1993).

    Article  ADS  Google Scholar 

  9. Sander, T. H. et al. Magnetoencephalography with a chip-scale atomic magnetometer. Biomed. Opt. Express 3, 981–990 (2012).

    Article  Google Scholar 

  10. Le Sage, D. et al. Optical magnetic imaging of living cells. Nature 496, 486–489 (2013).

    Article  ADS  Google Scholar 

  11. Jensen, K. et al. Non-invasive detection of animal nerve impulses with an atomic magnetometer operating near quantum limited sensitivity. Sci. Rep. 6, 29638 (2016).

    Article  ADS  Google Scholar 

  12. Swithenby, S. J. SQUIDs and their applications in the measurement of weak magnetic fields. J. Phys. E 13, 801–813 (1980).

    Article  ADS  Google Scholar 

  13. Kominis, I. K., Kornack, T. W., Allred, J. C. & Romalis, M. V. A subfemtotesla multichannel atomic magnetometer. Nature 422, 596–599 (2003).

    Article  ADS  Google Scholar 

  14. Wasilewski, W. et al. Quantum noise limited and entanglement-assisted magnetometry. Phys. Rev. Lett. 104, 133601 (2010).

    Article  ADS  Google Scholar 

  15. Bal, M., Deng, C., Orgiazzi, J.-L., Ong, F. R. & Lupascu, A. Ultrasensitive magnetic field detection using a single artificial atom. Nat. Commun. 3, 1324 (2012).

    Article  Google Scholar 

  16. Wildermuth, S. et al. Bose–Einstein condensates: microscopic magnetic-field imaging. Nature 435, 440 (2005).

    Article  ADS  Google Scholar 

  17. Vengalattore, M. et al. High-resolution magnetometry with a spinor Bose–Einstein condensate. Phys. Rev. Lett. 98, 200801 (2007).

    Article  ADS  Google Scholar 

  18. Ockeloen, C. F., Schmied, R., Riedel, M. F. & Treutlein, P. Quantum metrology with a scanning probe atom interferometer. Phys. Rev. Lett. 111, 143001 (2013).

    Article  ADS  Google Scholar 

  19. Müssel, W., Strobel, H., Linnemann, D., Hume, D. B. & Oberthaler, M. K. Scalable spin squeezing for quantum-enhanced magnetometry with Bose–Einstein condensates. Phys. Rev. Lett. 113, 103004 (2014).

    Article  ADS  Google Scholar 

  20. Ruster, T. et al. Entanglement-based DC magnetometry with separated ions. Phys. Rev. X 7, 031050 (2017).

    Google Scholar 

  21. Taylor, J. M. et al. High-sensitivity diamond magnetometer with nanoscale resolution. Nat. Phys. 4, 810–816 (2008).

    Article  Google Scholar 

  22. Balasubramanian, G. et al. Nanoscale imaging magnetometry with diamond spins under ambient conditions. Nature 455, 648–651 (2008).

    Article  ADS  Google Scholar 

  23. Maze, J. R. et al. Nanoscale magnetic sensing with an individual electronic spin in diamond. Nature 455, 644–647 (2008).

    Article  ADS  Google Scholar 

  24. Maiwald, R. et al. Stylus ion trap for enhanced access and sensing. Nat. Phys. 5, 551–554 (2009).

    Article  Google Scholar 

  25. Baumgart, I., Cai, J.-M., Retzker, A., Plenio, M. B. & Wunderlich, Ch Ultrasensitive magnetometer using a single atom. Phys. Rev. Lett. 116, 240801 (2016).

    Article  ADS  Google Scholar 

  26. Chalopin, T. et al. Quantum-enhanced sensing using non-classical spin states of a highly magnetic atom. Nat. Commun. 9, 4955 (2018).

  27. Signoles, A. et al. Coherent transfer between low-angular-momentum and circular Rydberg states. Phys. Rev. Lett. 118, 253603 (2017).

    Article  ADS  Google Scholar 

  28. Patsch, S. et al. Fast and accurate circularization of a Rydberg atom. Phys. Rev. A 97, 053418 (2018).

    Article  ADS  Google Scholar 

  29. Nguyen, T. L. et al. Towards quantum simulation with circular Rydberg atoms. Phys. Rev. X 8, 011032 (2018).

    Google Scholar 

  30. Hanneke, D., Fogwell Hoogerheide, S. & Gabrielse, G. Cavity control of a single-electron quantum cyclotron: measuring the electron magnetic moment. Phys. Rev. A 83, 052122 (2011).

    Article  ADS  Google Scholar 

Download references


The authors thank Ch. Koch and S. Patsch for useful discussions. The authors acknowledge financial support from the European Union under the Research and Innovation action project ‘RYSQ’ (640378) and from the Agence Nationale de la Recherche under project ‘SNOCAR’ (167754).

Author information

Authors and Affiliations



E.K.D., A.L., J.M.R., S.H., M.B. and S.G. contributed to the experimental set-up. E.K.D. and A.L. collected the data and analysed the results. S.G. supervised the experiment. All authors discussed the results and the manuscript.

Corresponding author

Correspondence to S. Gleyzes.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

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

Supplementary information

Supplementary Information

Supplementary Figures 1–8

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Dietsche, E.K., Larrouy, A., Haroche, S. et al. High-sensitivity magnetometry with a single atom in a superposition of two circular Rydberg states. Nat. Phys. 15, 326–329 (2019).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


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