Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Experimental demonstration of a hyper-entangled ten-qubit Schrödinger cat state

Nature Physics volume 6, pages 331–335 (2010)Cite this article

Abstract

Coherent manipulation of a large number of qubits and the generation of entangled states between them has been an important goal and benchmark in quantum information science, leading to various applications such as measurement-based quantum computing1 and high-precision quantum metrology2. However, the experimental preparation of multiparticle entanglement remains challenging. Using atoms3,4, entangled states of up to eight qubits have been created, and up to six photons5 have been entangled. Here, by exploiting both the photons’ polarization and momentum degrees of freedom, we experimentally generate hyper-entangled six-, eight- and ten-qubit Schrödinger cat states with verified genuine multi-qubit entanglement. We also demonstrate super-resolving phase measurements enhanced by entanglement, with a precision to beat the standard quantum limit. Modifications of the experimental set-up would enable the generation of other graph states up to ten qubits. Our method offers a way of expanding the effective Hilbert space and should provide a versatile test-bed for various quantum applications.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on SpringerLink
  • Instant access to the full article PDF.

USD 39.95

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Experimental set-up for the generation of hyper-entangled six-, eight- and ten-qubit Schrödinger cat states.
Figure 2: Experimental results for determination of the fidelities of the six- and eight-qubit cat states, showing phase super-resolution.
Figure 3: Experimental results for the ten-qubit cat states.

Similar content being viewed by others

References

  1. Raussendorf, R. & Briegel, H. J. A one-way quantum computer. Phys. Rev. Lett. 86, 5188–5191 (2001).

    Article  ADS  Google Scholar 

  2. Giovannetti, V., Lloyd, S. & Maccone, L. Quantum-enhanced measurements: Beating the standard quantum limit. Science 306, 1330–1336 (2004).

    Article  ADS  Google Scholar 

  3. Leibfried, D. et al. Creation of a six-atom ‘Schrödinger cat’ state. Nature 438, 639–642 (2005).

    Article  ADS  Google Scholar 

  4. Häffner, H. et al. Scalable multiparticle entanglement of trapped ions. Nature 438, 643–646 (2005).

    Article  ADS  Google Scholar 

  5. Lu, C.-Y. et al. Experimental entanglement of six photons in graph states. Nature Phys. 3, 91–95 (2007).

    Article  ADS  Google Scholar 

  6. Kok, P. et al. Linear optical quantum computing with photonic qubits. Rev. Mod. Phys. 79, 135–174 (2007).

    Article  ADS  Google Scholar 

  7. Ursin, R. et al. Entanglement-based quantum communication over 144 km. Nature Phys. 3, 481–486 (2007).

    Article  ADS  Google Scholar 

  8. Prevedel, R. et al. High-speed linear optics quantum computation using active feed-forward. Nature 445, 65–69 (2007).

    Article  ADS  Google Scholar 

  9. Politi, A., Cryan, M. J., Rarity, J. G., Yu, S. & O’Brien, J. L. Silica-on-silicon waveguide quantum circuits. Science 320, 646–649 (2008).

    Article  ADS  Google Scholar 

  10. Lanyon, B. P. et al. Simplifying quantum logic using higher-dimensional Hilbert spaces. Nature Phys. 5, 134–140 (2009).

    Article  ADS  Google Scholar 

  11. Tame, M. S. et al. Experimental realization of Deutsch’s algorithm in a one-way quantum computer. Phys. Rev. Lett. 98, 140501 (2007).

    Article  ADS  MathSciNet  Google Scholar 

  12. Lanyon, B.P. et al. Experimental demonstration of a complied version of Shor’s algorithm with quantum entanglement. Phys. Rev. Lett. 99, 250505 (2007).

    Article  ADS  Google Scholar 

  13. Kwiat, P. G. et al. New high-intensity source of polarization-entangled photon pairs. Phys. Rev. Lett. 75, 4337–4341 (1995).

    Article  ADS  Google Scholar 

  14. Kwiat, P. G. Hyper-entangled states. J. Mod. Opt. 44, 2173–2184 (1997).

    Article  ADS  MathSciNet  Google Scholar 

  15. Barreiro, J. T., Langford, N. K., Peter, N. A. & Kwiat, P. G. Generation of hyperentangled photon pairs. Phys. Rev. Lett. 95, 260501 (2005).

    Article  ADS  Google Scholar 

  16. Mair, A., Vaziri, A., Weihs, G. & Zeilinger, A. Entanglement of the orbital angular momentum states of photons. Nature 412, 313–316 (2001).

    Article  ADS  Google Scholar 

  17. Schuck, C., Huber, G., Kurtsiefer, C. & Weinfurter, H. Complete deterministic linear optics Bell state analysis. Phys. Rev. Lett. 96, 190501 (2006).

    Article  ADS  Google Scholar 

  18. Barreiro, J. T., Wei, T. C. & Kwiat, P. G. Beating the channel capacity limit for linear photonic superdense coding. Nature Phys. 4, 282–286 (2008).

    Article  Google Scholar 

  19. Barbieri, M., Martini, F. D., Mataloni, P., Vallone, G. & Cabello, A. Enhancing the violation of the Einstein–Podolsky–Rosen local realism by quantum hyperentanglement. Phys. Rev. Lett. 97, 140407 (2006).

    Article  ADS  Google Scholar 

  20. Chen, K. et al. Experimental realization of one-way quantum computing with two-photon four-qubit cluster states. Phys. Rev. Lett. 99, 120503 (2007).

    Article  ADS  Google Scholar 

  21. Vallone, G. et al. Active one-way quantum computation with two-photon four-qubit cluster states. Phys. Rev. Lett. 100, 160502 (2008).

    Article  ADS  Google Scholar 

  22. Greenberger, D. M., Horne, M., Shimony, A. & Zeilinger, A. Bell’s theorem without inequalities. Am. J. Phys. 58, 1131–1143 (1990).

    Article  ADS  MathSciNet  Google Scholar 

  23. Rarity, J. G. & Tapster, P. R. Three-particle entanglement from entangled photon pairs and a weak coherent state. Phys. Rev. A 59, R35–R38 (1999).

    Article  ADS  Google Scholar 

  24. Hein, M., Eisert, J. & Briegel, H. J. Multiparty entanglement in graph states. Phys. Rev. A 69, 062311 (2004).

    Article  ADS  MathSciNet  Google Scholar 

  25. Bourennane, M. et al. Experimental detection of multipartite entanglement using witness operators. Phys. Rev. Lett. 92, 087902 (2004).

    Article  ADS  Google Scholar 

  26. Leibfried, D. et al. Toward Heisenberg-limited spectroscopy with multiparticle entangled state. Science 304, 1476–1478 (2004).

    Article  ADS  Google Scholar 

  27. Dowling, J. P. Quantum optical metrology—the lowdown on high-N00N states. Contemp. Phys. 49, 125–143 (2008).

    Article  ADS  Google Scholar 

  28. Cabello, A. Bipartite Bell inequalities for hyperentangled states. Phys. Rev. Lett. 97, 140406 (2006).

    Article  ADS  MathSciNet  Google Scholar 

  29. Han, Y.-J., Raussendorf, R. & Duan, L.-M. Scheme for demonstration of fractional statistics of anyons in an exactly solvable model. Phys. Rev. Lett. 98, 150404 (2007).

    Article  ADS  MathSciNet  Google Scholar 

  30. Raussendorf, R., Harrington, J & Goyal, K. Topological fault-tolerance in cluster state quantum computation. New J. Phys. 9, 199 (2007).

    Article  ADS  MathSciNet  Google Scholar 

Download references

Acknowledgements

We thank J.P. Dowling and S.J. van Enk for helpful discussions. This work was supported by the National Natural Science Foundation of China, the Chinese Academy of Sciences and the National Fundamental Research Program (under Grant No 2006CB921900). This work was also supported by the Alexander von Humboldt Foundation, the ERC, the FWF (START prize) and the EU (SCALA, OLAQUI, QICS).

Author information

Authors and Affiliations

  1. Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China

    Wei-Bo Gao, Chao-Yang Lu, Xing-Can Yao, Ping Xu, Yu-Ao Chen, Cheng-Zhi Peng, Zeng-Bing Chen & Jian-Wei Pan

  2. Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Technikerstraße 21A, A-6020 Innsbruck, Austria

    Otfried Gühne

  3. Institut für Theoretische Physik, Universität Innsbruck, Technikerstraße 25, A–6020 Innsbruck, Austria

    Otfried Gühne

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

    Alexander Goebel, Yu-Ao Chen & Jian-Wei Pan

Authors
  1. Wei-Bo Gao
    View author publications

    Search author on:PubMed Google Scholar

  2. Chao-Yang Lu
    View author publications

    Search author on:PubMed Google Scholar

  3. Xing-Can Yao
    View author publications

    Search author on:PubMed Google Scholar

  4. Ping Xu
    View author publications

    Search author on:PubMed Google Scholar

  5. Otfried Gühne
    View author publications

    Search author on:PubMed Google Scholar

  6. Alexander Goebel
    View author publications

    Search author on:PubMed Google Scholar

  7. Yu-Ao Chen
    View author publications

    Search author on:PubMed Google Scholar

  8. Cheng-Zhi Peng
    View author publications

    Search author on:PubMed Google Scholar

  9. Zeng-Bing Chen
    View author publications

    Search author on:PubMed Google Scholar

  10. Jian-Wei Pan
    View author publications

    Search author on:PubMed Google Scholar

Contributions

C.-Y.L., W.-B.G. and J.-W.P. conceived the research; W.-B.G., X.-C.Y., P.X., A.G., Y.-A.C. and C.-Z.P. carried out the experiment; O.G. contributed theoretical analytic tools; W.-B.G., O.G. and C.-Y.L. analysed the data; C.-Y.L., O.G., W.-B.G. and J.-W.P. wrote the paper; J.-W.P. and Z.-B.C. supervised the whole project.

Corresponding authors

Correspondence to Zeng-Bing Chen or Jian-Wei Pan.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

Supplementary Information (PDF 494 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Gao, WB., Lu, CY., Yao, XC. et al. Experimental demonstration of a hyper-entangled ten-qubit Schrödinger cat state. Nature Phys 6, 331–335 (2010). https://doi.org/10.1038/nphys1603

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue date:

  • DOI: https://doi.org/10.1038/nphys1603

This article is cited by

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing