Letter | Published:

Room-temperature entanglement between single defect spins in diamond

Nature Physics volume 9, pages 139143 (2013) | Download Citation

Abstract

Entanglement is the central yet fleeting phenomenon of quantum physics. Once being considered a peculiar counter-intuitive property of quantum theory1, it has developed into the most central element of quantum technology. Consequently, there have been a number of experimental demonstrations of entanglement between photons2, atoms3, ions4 and solid-state systems such as spins or quantum dots5,6,7, superconducting circuits8,9 and macroscopic diamond10. Here we experimentally demonstrate entanglement between two engineered single solid-state spin quantum bits (qubits) at ambient conditions. Photon emission of defect pairs reveals ground-state spin correlation. Entanglement (fidelity = 0.67±0.04) is proved by quantum state tomography. Moreover, the lifetime of electron spin entanglement is extended to milliseconds by entanglement swapping to nuclear spins. The experiments mark an important step towards a scalable room-temperature quantum device being of potential use in quantum information processing as well as metrology.

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Acknowledgements

The authors would like to acknowledge financial support by the EU through SQUTEC and Diamant, as well as the DFG through SFB/TR21, the research groups 1493 ‘Diamond quantum materials’ and 1482 as well as the Volkswagen Foundation. We thank Y. Wang, R. Kolesov, R. Stöhr, G. Waldherr, S. Steinert, T. Staudacher, J. Michl, C. Burk, E6, J. Biamonte, H. Fedder, F. Reinhard and F. Shi for discussions and support.

Author information

Affiliations

  1. 3. Physikalisches Institut, Research Center SCoPE, and IQST, Universität Stuttgart, 70569 Stuttgart, Germany

    • F. Dolde
    • , I. Jakobi
    • , B. Naydenov
    • , N. Zhao
    • , P. Neumann
    • , F. Jelezko
    •  & J. Wrachtrup
  2. Institut für Quantenoptik, and IQST, Universität Ulm, 89081 Ulm, Germany

    • B. Naydenov
    •  & F. Jelezko
  3. RUBION, Ruhr Universität Bochum, 44780 Bochum, Germany

    • S. Pezzagna
    •  & J. Meijer
  4. GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany

    • C. Trautmann
  5. Technische Universität Darmstadt, 64289 Darmstadt, Germany

    • C. Trautmann

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Contributions

F.D., I.J. and B.N. carried out the experiments. S.P., C.T. and J.M. prepared implantation masks and samples. P.N., F.J. and J.W. supervised experiments. N.Z. analysed experimental data. F.D., P.N., I.J. and J.W. wrote the paper.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to F. Dolde or B. Naydenov.

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DOI

https://doi.org/10.1038/nphys2545

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