Letter | Published:

Decoherence-protected memory for a single-photon qubit

Nature Photonicsvolume 12pages1821 (2018) | Download Citation


Distributed quantum computation in a quantum network1,2,3 is based on the idea that qubits can be preserved and efficiently exchanged between long-lived, stationary network nodes via photonic links4. Although long qubit lifetimes have been observed5,6,7,8,9,10, and non-qubit excitations have been memorized11,12,13,14, the long-lived storage and efficient retrieval of a photonic qubit by means of a light–matter interface15,16,17,18,19,20 remains an outstanding challenge. Here, we report on a qubit memory based on a single atom coupled to a high-finesse optical resonator. By mapping the qubit between an interface basis with strong light–matter coupling and a memory basis with low decoherence, we achieve a coherence time exceeding 100 ms with a time-independent storage-and-retrieval efficiency of 22%. The former constitutes an improvement by two orders of magnitude21,22 and thus implements an efficient photonic qubit memory with a coherence time that exceeds the lower bound needed for direct qubit teleportation in a global quantum internet.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Additional information

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


  1. 1.

    Briegel, H.-J., Dür, W., Cirac, J. I. & Zoller, P. Quantum repeaters: the role of imperfect local operations in quantum communication. Phys. Rev. Lett. 81, 5932–5935 (1998).

  2. 2.

    Kimble, H. J. The quantum internet. Nature 453, 1023–1030 (2008).

  3. 3.

    Razavi, M., Piani, M. & Lütkenhaus, N. Quantum repeaters with imperfect memories: Cost and scalability. Phys. Rev. A 80, 032301 (2009).

  4. 4.

    DiVincenzo, D. P. The physical implementation of quantum computation. Fortschr. Phys. 48, 771–783 (2000).

  5. 5.

    Langer, C. et al. Long-lived qubit memory using atomic ions. Phys. Rev. Lett. 95, 060502 (2005).

  6. 6.

    Maurer, P. C. et al. Room-temperature quantum bit memory exceeding one second. Science 336, 1283–1286 (2012).

  7. 7.

    Steger, M. et al. Quantum information storage for over 180 s using donor spins in a 28Si “semiconductor vacuum”. Science 336, 1280–1283 (2012).

  8. 8.

    Bar-Gill, N., Pham, L. M., Jarmola, A., Budker, D. & Walsworth, R. L. Solid-state electronic spin coherence time approaching one second. Nat. Commun. 4, 1743 (2013).

  9. 9.

    Zhong, M. et al. Optically addressable nuclear spins in a solid with a six-hour coherence time. Nature 517, 177–180 (2015).

  10. 10.

    Yang, J. et al. Coherence preservation of a single neutral atom qubit transferred between magic-intensity optical traps. Phys. Rev. Lett. 117, 123201 (2016).

  11. 11.

    Zhao, B. et al. A millisecond quantum memory for scalable quantum networks. Nat. Phys. 5, 95–99 (2009).

  12. 12.

    Radnaev, A. G. et al. A quantum memory with telecom-wavelength conversion. Nat. Phys. 6, 894–899 (2010).

  13. 13.

    Bao, X.-H. et al. Efficient and long-lived quantum memory with cold atoms inside a ring cavity. Nat. Phys. 8, 517–521 (2012).

  14. 14.

    Yang, S.-J., Wang, X.-J., Bao, X.-H. & Pan, J.-W. An efficient quantum light–matter interface with sub-second lifetime. Nat. Photon. 10, 381–384 (2016).

  15. 15.

    Julsgaard, B., Sherson, J., Cirac, J. I., Fiurášek, J. & Polzik, E. S. Experimental demonstration of quantum memory for light. Nature 432, 482–486 (2004).

  16. 16.

    Choi, K. S., Deng, H., Laurat, J. & Kimble, H. J. Mapping photonic entanglement into and out of a quantum memory. Nature 452, 67–71 (2008).

  17. 17.

    Clausen, C., Bussières, F., Afzelius, M. & Gisin, N. Quantum storage of heralded polarization qubits in birefringent and anisotropically absorbing materials. Phys. Rev. Lett. 108, 190503 (2012).

  18. 18.

    Sprague, M. R. et al. Broadband single-photon-level memory in a hollow-core photonic crystal fibre. Nat. Photon. 8, 287–291 (2014).

  19. 19.

    Gouraud, B., Maxein, D., Nicolas, A., Morin, O. & Laurat, J. Demonstration of a memory for tightly guided light in an optical nanofiber. Phys. Rev. Lett. 114, 180503 (2015).

  20. 20.

    Sayrin, C., Clausen, C., Albrecht, B., Schneeweiss, P. & Rauschenbeutel, A. Storage of fiber-guided light in a nanofiber-trapped ensemble of cold atoms. Optica 2, 353–356 (2015).

  21. 21.

    Riedl, S. et al. Bose-Einstein condensate as a quantum memory for a photonic polarisation qubit. Phys. Rev. A 85, 022318 (2012).

  22. 22.

    Xu, Z. et al. Long lifetime and high-fidelity quantum memory of photonic polarisation qubit by lifting Zeeman degeneracy. Phys. Rev. Lett. 111, 240503 (2013).

  23. 23.

    Munro, W. J. et al. Quantum communication without the necessity of quantum memories. Nat. Photon. 6, 777–781 (2012).

  24. 24.

    Bennett, C. H. et al. Teleporting an unknown quantum state via dual classical and Einstein-Podolsky-Rosen channels. Phys. Rev. Lett. 70, 1895–1899 (1993).

  25. 25.

    Treutlein, P., Hommelhoff, P., Steinmetz, T., Hänsch, T. W. & Reichel, J. Coherence in microchip traps. Phys. Rev. Lett. 92, 203005 (2004).

  26. 26.

    Specht, H. P. et al. A single-atom quantum memory. Nature 473, 190–193 (2011).

  27. 27.

    Ruster, T. et al. A long-lived Zeeman trapped-ion qubit. Appl. Phys. B 112, 254 (2016).

  28. 28.

    Neuzner, A., Körber, M., Morin, O., Ritter, S. & Rempe, G. Interference and dynamics of light from a distance-controlled atom pair in an optical cavity. Nat. Photon. 10, 303–306 (2016).

  29. 29.

    Boozer, A. D., Boca, A., Miller, R., Northup, T. E. & Kimble, H. J. Cooling to the ground state of axial motion for one atom strongly coupled to an optical cavity. Phys. Rev. Lett. 97, 083602 (2006).

  30. 30.

    Reiserer, A., Nölleke, C., Ritter, S. & Rempe, G. Ground-state cooling of a single atom at the center of an optical cavity. Phys. Rev. Lett. 110, 223003 (2013).

  31. 31.

    Dilley, J., Nisbet-Jones, P., Shore, B. W. & Kuhn, A. Single-photon absorption in coupled atom-cavity systems. Phys. Rev. A 85, 023834 (2012).

  32. 32.

    Uphoff, M., Brekenfeld, M., Rempe, G. & Ritter, S. An integrated quantum repeater at telecom wavelength with single atoms in optical fiber cavities. Appl. Phys. B 122, 46 (2016).

Download references


We thank B. Wang for the development of the hardware and S. Dürr, L. Li and M. Uphoff for discussion. This work was supported by the Bundesministerium für Bildung und Forschung via the Verbund Q.comand by the Deutsche Forschungsgemeinschaft via the excellence cluster Nanosystems Initiative Munich (NIM).

Author information

Author notes

    • A. Neuzner

    Present address: OHB System AG, Weβling, Germany

    • S. Ritter

    Present address: TOPTICA Photonics AG, Graefelfing, Germany

  1. M. Körber and O. Morin contributed equally to this work.


  1. Max-Planck-Institut für Quantenoptik, Garching, Germany

    • M. Körber
    • , O. Morin
    • , S. Langenfeld
    • , A. Neuzner
    • , S. Ritter
    •  & G. Rempe


  1. Search for M. Körber in:

  2. Search for O. Morin in:

  3. Search for S. Langenfeld in:

  4. Search for A. Neuzner in:

  5. Search for S. Ritter in:

  6. Search for G. Rempe in:


M.K., O.M., A.N., S.R. and G.R. conceived the experiment. M.K., O.M. and S.L. performed the experiment. M.K., O.M., S.L., S.R. and G.R. evaluated the data. All authors contributed to the writing of the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to M. Körber.

Supplementary information

  1. Supplementary Information

    Supplementary text

About this article

Publication history