Skip to main content
Log in

Quantum correlations for bipartite continuous-variable systems

  • Published:
Quantum Information Processing Aims and scope Submit manuscript

Abstract

Two quantum correlations Q and \(Q_\mathcal P\) for \((m+n)\)-mode continuous-variable systems are introduced in terms of average distance between the reduced states under the local Gaussian positive operator-valued measurements, and analytical formulas of these quantum correlations for bipartite Gaussian states are provided. It is shown that the product states do not contain these quantum correlations, and conversely, all \((m+n)\)-mode Gaussian states with zero quantum correlations are product states. Generally, \(Q\ge Q_{\mathcal P}\), but for the symmetric two-mode squeezed thermal states, these quantum correlations are the same and a computable formula is given. In addition, Q is compared with Gaussian geometric discord for symmetric squeezed thermal states.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1

Similar content being viewed by others

References

  1. Horodecki, R., Horodecki, P., Horodecki, M., Horodecki, K.: Quantum entanglement. Rev. Mod. Phys. 81, 865 (2009)

    Article  ADS  MathSciNet  MATH  Google Scholar 

  2. Gühne, O., Tóth, G.: Entanglement detection. Phys. Rep. 474, 1 (2009)

    Article  ADS  MathSciNet  Google Scholar 

  3. Ollivier, H., Zurek, W .H.: Quantum discord: a measure of the quantumness of correlations. Phys. Rev. Lett. 88, 017901 (2001)

    Article  ADS  MATH  Google Scholar 

  4. Luo, S.: Quantum discord for two-qubit systems. Phys. Rev. A 77, 042303 (2008)

    Article  ADS  Google Scholar 

  5. Datta, A., Shaji, A., Caves, C.M.: Quantum discord and the power of one qubit. Phys. Rev. Lett. 100, 050502 (2008)

    Article  ADS  Google Scholar 

  6. Piani, M., Horodecki, P., Horodecki, R.: No-local-broadcasting theorem for multipartite quantum correlations. Phys. Rev. Lett. 100, 090502 (2008)

    Article  ADS  Google Scholar 

  7. Luo, S., Fu, S.: Measurement-induced nonlocality. Phys. Rev. Lett. 106, 120401 (2011)

    Article  ADS  MATH  Google Scholar 

  8. Guo, Y., Hou, J.-C.: Local channels preserving the states without measurement-induced nonlocality. J. Phys. A Math. Theor. 46, 325301 (2013)

    Article  ADS  MathSciNet  MATH  Google Scholar 

  9. Guo, Y., Hou, J.-C.: A class of separable quantum states. J. Phys. A Math. Theor. 45, 505303 (2012)

    Article  MathSciNet  MATH  Google Scholar 

  10. Mista Jr., L., Tatham, R., Girolami, D., Korolkova, N., Adesso, G.: Measurement-induced disturbances and nonclassical correlations of Gaussian states. Phys. Rev. A 83, 042325 (2011)

    Article  ADS  Google Scholar 

  11. Giorda, P., Paris, M.G.A.: Gaussian quantum discord. Phys. Rev. Lett. 105, 020503 (2010)

    Article  ADS  Google Scholar 

  12. Adesso, G., Datta, A.: Quantum versus classical correlations in Gaussian states. Phys. Rev. Lett. 105, 030501 (2010)

    Article  ADS  Google Scholar 

  13. Su, X.-L.: Applying Gaussian quantum discord to quantum key distribution. Chin. Sci. Bull. 59(11), 1083–1090 (2014)

    Article  Google Scholar 

  14. Adesso, G., Girolami, D.: Gaussian geometric discord. Int. J. Quantum Inf. 9, 1773–1786 (2011)

    Article  MATH  Google Scholar 

  15. Liu, D., Zhao, X., Long, G.-L.: Multiple entropy measures for multi-particle pure quantum state. Commun. Theor. Phys. 54, 825 (2010)

    Article  ADS  MATH  Google Scholar 

  16. Cao, Y., Li, H., Long, G.-L.: Entanglement of linear cluster states in terms of averaged entropies. Chin. Sci. Bull. 58, 48–52 (2013)

    Article  Google Scholar 

  17. Guo, Y., Li, X.-L., Li, B., Fan, H.: Quantum correlation induced by the average distance between the reduced states. Int. J. Theor. Phys. 54(6), 2022–2030 (2015)

    Article  MATH  Google Scholar 

  18. Braunstein, S.L., Van Loock, P.: Quantum information with continuous variables. Rev. Mod. Phys. 77, 513 (2005)

    Article  ADS  MathSciNet  MATH  Google Scholar 

  19. Wang, X.-B., Hiroshima, T., Tomita, A., Hayashi, M.: Quantum information with Gaussian states. Phys. Rep. 448, 1–111 (2007)

    Article  ADS  MathSciNet  Google Scholar 

  20. Anders, J.: Estimating the degree of entanglement of unknown Gaussian states. arXiv:quant-ph/0610263 (2006)

  21. Giedke, G., Cirac, J.I.: Characterization of Gaussian operations and distillation of Gaussian states. Phys. Rev. A 66, 032316 (2002)

    Article  ADS  Google Scholar 

  22. Scutaru, H.: Fidelity for displaced squeezed states and the oscillator semigroup. J. Phys. A Math. Gen. 31(15), 3659–3663 (1998)

    Article  ADS  MathSciNet  MATH  Google Scholar 

  23. Xu, J.: Which bipartite states are lazy. Int. J. Theor. Phys. 54, 860 (2015)

    Article  MathSciNet  MATH  Google Scholar 

  24. Bowen, W.P., Schnabel, R., Lam, P.K., Ralph, T.C.: Experimental characterization of continuous-variable entanglement. Phys. Rev. A 69, 012304 (2004)

    Article  ADS  Google Scholar 

  25. Giedke, G., Cirac, J.I.: Experimental criteria for steering and the Einstein–Podolsky–Rosen paradox. Phys. Rev. A 80, 032112 (2009)

    Article  Google Scholar 

Download references

Acknowledgements

The authors thank all referees for their many helpful comments. This work is partially supported by Natural Science Foundation of China (11671006, 11671294) and Outstanding Youth Foundation of Shanxi Province (201701D211001).

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Xiaofei Qi.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Ma, R., Hou, J., Qi, X. et al. Quantum correlations for bipartite continuous-variable systems. Quantum Inf Process 17, 98 (2018). https://doi.org/10.1007/s11128-018-1866-1

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1007/s11128-018-1866-1

Keywords

Navigation