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ABSTRACT 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. Access through your institution Buy or subscribe This is a preview of subscription content, access via your institution ACCESS OPTIONS

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Contact customer support SIMILAR CONTENT BEING VIEWED BY OTHERS MINUTE-SCALE SCHRÖDINGER-CAT STATE OF SPIN-5/2 ATOMS Article 01 November 2024 HIGH FREQUENCY MAGNETOMETRY WITH AN ENSEMBLE OF

SPIN QUBITS IN HEXAGONAL BORON NITRIDE Article Open access 06 January 2024 QUANTUM-ENHANCED SENSING ON OPTICAL TRANSITIONS THROUGH FINITE-RANGE INTERACTIONS Article 30 August 2023 DATA

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Google Scholar  Download references ACKNOWLEDGEMENTS 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 Author notes * These authors

contributed equally: E. K. Dietsche, A. Larrouy. AUTHORS AND AFFILIATIONS * Laboratoire Kastler Brossel, Collège de France, CNRS, ENS-Université PSL, Sorbonne Université, Paris, France E. K.

Dietsche, A. Larrouy, S. Haroche, J. M. Raimond, M. Brune & S. Gleyzes Authors * E. K. Dietsche View author publications You can also search for this author inPubMed Google Scholar * A.

Larrouy View author publications You can also search for this author inPubMed Google Scholar * S. Haroche View author publications You can also search for this author inPubMed Google

Scholar * J. M. Raimond View author publications You can also search for this author inPubMed Google Scholar * M. Brune View author publications You can also search for this author inPubMed 

Google Scholar * S. Gleyzes View author publications You can also search for this author inPubMed Google Scholar CONTRIBUTIONS 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

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Reprints and permissions ABOUT THIS ARTICLE 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). https://doi.org/10.1038/s41567-018-0405-4 Download citation * Received: 25 July 2018 * Accepted: 10 December 2018 * Published: 21

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