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Mapping photonic entanglement into and out of a quantum memory

Nature volume 452, pages 67–71 (2008)Cite this article

Abstract

Developments in quantum information science1 rely critically on entanglement—a fundamental aspect of quantum mechanics that causes parts of a composite system to show correlations stronger than can be explained classically2. In particular, scalable quantum networks require the capability to create, store and distribute entanglement among distant matter nodes by means of photonic channels3. Atomic ensembles can play the role of such nodes4. So far, in the photon-counting regime, heralded entanglement between atomic ensembles has been successfully demonstrated through probabilistic protocols5,6. But an inherent drawback of this approach is the compromise between the amount of entanglement and its preparation probability, leading to intrinsically low count rates for high entanglement. Here we report a protocol where entanglement between two atomic ensembles is created by coherent mapping of an entangled state of light. By splitting a single photon7,8,9 and performing subsequent state transfer, we separate the generation of entanglement and its storage10. After a programmable delay, the stored entanglement is mapped back into photonic modes with overall efficiency of 17%. Together with improvements in single-photon sources11, our protocol will allow ‘on-demand’ entanglement of atomic ensembles, a powerful resource for quantum information science.

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Figure 1: Overview of the experiment.
Figure 2: Single-photon storage and retrieval for a single ensemble.
Figure 3: Entanglement for the input and output optical modes.

References

  1. Zoller, P. et al. Quantum information processing and communication. Strategic report on current status, visions and goals for research in Europe. Eur. Phys. J. D 36, 203–228 (2005)

    Article  ADS  CAS  Google Scholar 

  2. Clauser, J. F. & Shimony, A. Bell’s theorem. Experimental tests and implications. Rep. Prog. Phys. 41, 1881–1927 (1978)

    Article  ADS  CAS  Google Scholar 

  3. Briegel, H.-J., van Enk, S. J., Cirac, J. I. & Zoller, P. Quantum networks and multi-particle entanglement, in The Physics of Quantum Information (eds Bouwmeester, D., Ekert, A. K. & Zeilinger, A.) (Springer, Berlin, 2000)

    Google Scholar 

  4. Duan, L.-M., Lukin, M. D., Cirac, J. I. & Zoller, P. Long-distance quantum communication with atomic ensembles and linear optics. Nature 414, 413–418 (2001)

    Article  ADS  CAS  Google Scholar 

  5. Chou, C. W. et al. Measurement-induced entanglement for excitation stored in remote atomic ensembles. Nature 438, 828–832 (2005)

    Article  ADS  CAS  Google Scholar 

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

    Article  ADS  CAS  Google Scholar 

  7. Tan, S. M., Walls, D. F. & Collett, M. J. Nonlocality of a single photon. Phys. Rev. Lett. 66, 252–255 (1991)

    Article  ADS  CAS  Google Scholar 

  8. Hessmo, B., Usachev, P., Hoshang, H. & Gunner, B. Experimental demonstration of single photon nonlocality. Phys. Rev. Lett. 92, 180401 (2004)

    Article  ADS  Google Scholar 

  9. Jacques, V. et al. Experimental realization of Wheeler’s delayed-choice gedanken experiment. Science 315, 966–968 (2007)

    Article  ADS  CAS  Google Scholar 

  10. Sangouard, N. et al. Long-distance entanglement distribution with single-photon sources. Phys. Rev. A 76, 050301(R) (2007)

    Article  ADS  Google Scholar 

  11. Lounis, B. & Orrit, M. Single-photon sources. Rep. Prog. Phys. 68, 1129–1179 (2005)

    Article  ADS  CAS  Google Scholar 

  12. Sherson, J. F. et al. Quantum teleportation between light and matter. Nature 443, 557–560 (2006)

    Article  ADS  CAS  Google Scholar 

  13. Laurat, J. et al. Efficient retrieval of a single excitation stored in an atomic ensemble. Opt. Express 14, 6912–6918 (2006)

    Article  ADS  Google Scholar 

  14. Thompson, J. K., Simon, J., Loh, H. & Vuletić, V. A high-brightness source of narrowband, identical photon pairs. Science 313, 74–77 (2006)

    Article  ADS  CAS  Google Scholar 

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

    Article  ADS  CAS  Google Scholar 

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

    Article  ADS  Google Scholar 

  17. Laurat, J., Choi, K. S., Deng, H., Chou, C.-W. & Kimble, H. J. Heralded entanglement between atomic ensembles: Preparation, decoherence, and scaling. Phys. Rev. Lett. 99, 180504 (2007)

    Article  ADS  CAS  Google Scholar 

  18. Laurat, J. et al. Towards experimental entanglement connection with atomic ensembles in the single excitation regime. New J. Phys. 9, 207–220 (2007)

    Article  ADS  Google Scholar 

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

    Article  ADS  CAS  Google Scholar 

  20. Harris, S. E. Electromagnetically induced transparency. Phys. Today 50, 36–40 (1997)

    Article  CAS  Google Scholar 

  21. Hau, L. V., Harris, S. E., Dutton, Z. & Behroozi, C. H. Light speed reduction to 17 metres per second in an ultracold atomic gas. Nature 397, 594–598 (1999)

    Article  ADS  CAS  Google Scholar 

  22. Kash, M. M. et al. Ultraslow group velocity and enhanced nonlinear optical effects in a coherently driven hot atomic gas. Phys. Rev. Lett. 82, 5229–5232 (1999)

    Article  ADS  CAS  Google Scholar 

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

    Article  ADS  CAS  Google Scholar 

  24. Liu, C., Dutton, Z., Behroozi, C. H. & Hau, L. V. Observation of coherent optical information storage in an atomic medium using halted light pulses. Nature 409, 490–493 (2001)

    Article  ADS  CAS  Google Scholar 

  25. Phillips, D. F., Fleischhauer, A., Mair, A., Walsworth, R. L. & Lukin, M. D. Storage of light in atomic vapor. Phys. Rev. Lett. 86, 783–786 (2001)

    Article  ADS  CAS  Google Scholar 

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

    Article  ADS  Google Scholar 

  27. Eisaman, M. D. et al. Electromagnetically induced transparency with tunable single-photon pulses. Nature 438, 837–841 (2005)

    Article  ADS  CAS  Google Scholar 

  28. Simon, J., Tanji, H., Ghosh, S. & Vuletić, V. Single-photon bus connecting spin-wave quantum memories. Nature Phys. 3, 765–769 (2007)

    Article  ADS  CAS  Google Scholar 

  29. Wootters, W. K. Entanglement of formation of an arbitrary state of two qubits. Phys. Rev. Lett. 80, 2245–2248 (1998)

    ADS  CAS  MATH  Google Scholar 

  30. van Enk, S. J. Single-particle entanglement. Phys. Rev. A. 72, 064306 (2005)

    Article  ADS  Google Scholar 

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

    Article  ADS  CAS  Google Scholar 

  32. Ringot, J., Szriftgiser, P. & Garreau, J. C. Subrecoil Raman spectroscopy of cold cesium atoms. Phys. Rev. A. 65, 013403 (2001)

    Article  ADS  Google Scholar 

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

    Article  ADS  CAS  Google Scholar 

  34. Eisaman, M. D. et al. Shaping quantum pulses of light via coherent atomic memory. Phys. Rev. Lett. 93, 233602 (2004)

    Article  ADS  CAS  Google Scholar 

  35. Balić, V., Braje, D. A., Kolchin, P., Yin, G. Y. & Harris, S. E. Generation of paired photons with controllable waveforms. Phys. Rev. Lett. 94, 183601 (2005)

    Article  ADS  Google Scholar 

  36. Novikova, I. et al. Optimal control of light pulse storage and retrieval. Phys. Rev. Lett. 98, 243602 (2007)

    Article  ADS  Google Scholar 

  37. Gorshkov, A. V., André, A., Fleischhauer, M., Sørensen, A. S. & Lukin, M. D. Universal approach to optimal photon storage in atomic media. Phys. Rev. Lett. 98, 123601 (2007)

    Article  ADS  Google Scholar 

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Acknowledgements

We acknowledge our ongoing collaboration with S. J. van Enk. This research is supported by the Intelligence Advanced Research Projects Activity and by the National Science Foundation. H.D. acknowledges support as Fellow of the Center for the Physics of Information at Caltech. J.L. acknowledges financial support from the European Union (Marie Curie Fellowship).

Author Contributions K.S.C. and H.D. are the principal contributors to the experiment in equal measure.

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Author notes

  1. J. Laurat

    Present address: Present address: Laboratoire Kastler Brossel, Université P. et M. Curie, Ecole Normale Superieure et CNRS, UPMC Case 74, 4 place Jussieu, 75252 Paris Cedex 05, France.,

Authors and Affiliations

  1. Norman Bridge Laboratory of Physics 12-33, California Institute of Technology, Pasadena, California 91125, USA,

    K. S. Choi, H. Deng, J. Laurat & H. J. Kimble

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  1. K. S. Choi
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  2. H. Deng
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  3. J. Laurat
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  4. H. J. Kimble
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Correspondence to H. J. Kimble.

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Choi, K., Deng, H., Laurat, J. et al. Mapping photonic entanglement into and out of a quantum memory. Nature 452, 67–71 (2008). https://doi.org/10.1038/nature06670

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