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A millisecond quantum memory for scalable quantum networks

Nature Physics volume 5, pages 9599 (2009) | Download Citation

Abstract

Scalable quantum-information processing requires the capability of storing quantum states1,2. In particular, a long-lived storable and retrievable quantum memory for single excitations is of key importance to long-distance quantum communication with atomic ensembles and linear optics3,4,5,6,7. Although atomic memories for classical light8 and continuous variables9 have been demonstrated with millisecond storage time, lifetimes of only around 10 μs have been reported for quantum memories storing single excitations10,11,12,13. Here we present an experimental investigation into extending the storage time of quantum memory for single excitations. We identify and isolate distinct mechanisms responsible for the decoherence of spin waves in atomic-ensemble-based quantum memories. By exploiting magnetic-field-insensitive states—so-called clock states—and generating a long-wavelength spin wave to suppress dephasing, we succeed in extending the storage time of the quantum memory to 1 ms. Our result represents an important advance towards long-distance quantum communication and should provide a realistic approach to large-scale quantum information processing.

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References

  1. 1.

    , , & Quantum repeaters: The role of imperfect local operations in quantum communication. Phys. Rev. Lett. 81, 5932–5935 (1998).

  2. 2.

    , & A scheme for efficient quantum computation with linear optics. Nature 409, 46–52 (2001).

  3. 3.

    , , & Long-distance quantum communication with atomic ensembles and linear optics. Nature 414, 413–418 (2001).

  4. 4.

    , , , & Robust creation of entanglement between remote memory qubits. Phys. Rev. Lett. 98, 240502 (2007).

  5. 5.

    , , , & Fault-tolerant quantum repeater with atomic ensembles and linear optics. Phys. Rev. A 76, 022329 (2007).

  6. 6.

    , & Fast and robust approach to long-distance quantum communication with atomic ensembles. Phys. Rev. A 76, 012301 (2007).

  7. 7.

    , , & Multiplexed memory insensitive quantum repeaters. Phys. Rev. Lett. 98, 060502 (2007).

  8. 8.

    , , & Observation of coherent optical information storage in an atomic medium using halted light pulses. Nature 409, 490–493 (2001).

  9. 9.

    , , , & Experimental demonstration of quantum memory for light. Nature 432, 482–486 (2004).

  10. 10.

    et al. Deterministic single photons via conditional quantum evolution. Phys. Rev. Lett. 97, 013601 (2006).

  11. 11.

    et al. Deterministic and storable single-photon source based on quantum memory. Phys. Rev. Lett. 97, 173004 (2006).

  12. 12.

    , , & Interfacing collective atomic excitations and single photons. Phys. Rev. Lett. 98, 183601 (2007).

  13. 13.

    et al. Functional quantum nodes for entanglement distribution over scalable quantum networks. Science 316, 1316–1320 (2007).

  14. 14.

    et al. Conditional control of the quantum states of remote atomic memories for quantum networking. Nature Phys. 2, 844–848 (2006).

  15. 15.

    et al. Quantum interference of electromagnetic fields from remote quantum memories. Phys. Rev. Lett. 98, 113602 (2007).

  16. 16.

    et al. Synchronized independent narrow-band single photons and efficient generation of photonic entanglement. Phys. Rev. Lett. 98, 180503 (2007).

  17. 17.

    et al. Memory-built-in quantum teleportation with photonic and atomic qubits. Nature Phys. 4, 103–107 (2008).

  18. 18.

    et al. Experimental demonstration of a BDCZ quantum repeater node. Nature 454, 1098–1101 (2008).

  19. 19.

    , , , & Control of decoherence in the generation of photon pairs from atomic ensembles. Phys. Rev. A 72, 053809 (2005).

  20. 20.

    , , & Mapping photonic entanglement into and out of a quantum memory. Nature 452, 67–71 (2008).

  21. 21.

    , , & Effect of cold collisions on spin coherence and resonance shifts in a magnetically trapped ultracold gas. Phys. Rev. A 66, 053616 (2002).

  22. 22.

    et al. Demonstration of a stable atom–photon entanglement source for quantum repeaters. Phys. Rev. Lett. 99, 180505 (2007).

  23. 23.

    et al. Direct measurement of decoherence for entanglement between a photon and stored atomic excitation. Phys. Rev. Lett. 97, 113603 (2006).

  24. 24.

    , , & Single-photon generation from stored excitation in an atomic ensemble. Phys. Rev. Lett. 92, 213601 (2004).

  25. 25.

    & Decoherence in collective quantum memories for photons. Phys. Rev. A 72, 022327 (2005).

  26. 26.

    , & Optical dipole traps for neutral atoms. Adv. Atom. Mol. Opt. Phys. 42, 95–170 (2000).

  27. 27.

    , , , & Quantum phase transition from a superfluid to a Mott insulator in a gas of ultracold atoms. Nature 415, 39–44 (2002).

  28. 28.

    , , & Stopped light with storage times greater than one second using electromagnetically induced transparency in a solid. Phys. Rev. Lett. 95, 063601 (2005).

  29. 29.

    et al. Robust and efficient quantum repeaters with atomic ensembles and linear optics. Phys. Rev. A 77, 062301 (2008).

  30. 30.

    & Dark-state polaritons in electromagnetically induced transparency. Phys. Rev. Lett. 84, 5094–5097 (2000).

  31. 31.

    et al. Storage and retrieval of single photons transmitted between remote quantum memories. Nature 438, 833–836 (2005).

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Acknowledgements

We acknowledge M. Fleischhauer and Y. J. Deng for useful discussions. This work was supported by the Deutsche Forschungsgemeinschaft (DFG), the Alexander von Humboldt Foundation, an ERC grant, the National Fundamental Research Program (grant No. 2006CB921900), the CAS and the NNSFC.

Author information

Author notes

    • Bo Zhao
    •  & Yu-Ao Chen

    These authors contributed equally to this work

Affiliations

  1. Physikalisches Institut, Universität Heidelberg, Philosophenweg 12, D-69120 Heidelberg, Germany

    • Bo Zhao
    • , Yu-Ao Chen
    • , Xiao-Hui Bao
    • , Thorsten Strassel
    • , Chih-Sung Chuu
    • , Zhen-Sheng Yuan
    • , Shuai Chen
    •  & Jian-Wei Pan
  2. Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China

    • Yu-Ao Chen
    • , Xiao-Hui Bao
    • , Xian-Min Jin
    • , Zhen-Sheng Yuan
    •  & Jian-Wei Pan
  3. Atominstitut der Österreichischen Universitäten, TU-Wien, A-1020 Vienna, Austria

    • Jörg Schmiedmayer

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Corresponding authors

Correspondence to Yu-Ao Chen or Jian-Wei Pan.

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DOI

https://doi.org/10.1038/nphys1153

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