OSA's Digital Library

Journal of the Optical Society of America B

Journal of the Optical Society of America B


  • Editor: Grover Swartzlander
  • Vol. 31, Iss. 9 — Sep. 1, 2014
  • pp: 2045–2050

Quantifying the source of enhancement in experimental continuous variable quantum illumination

Sammy Ragy, Ivano Ruo Berchera, Ivo P. Degiovanni, Stefano Olivares, Matteo G. A. Paris, Gerardo Adesso, and Marco Genovese  »View Author Affiliations

JOSA B, Vol. 31, Issue 9, pp. 2045-2050 (2014)

View Full Text Article

Enhanced HTML    Acrobat PDF (310 KB)

Browse Journals / Lookup Meetings

Browse by Journal and Year


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools



A quantum illumination protocol exploits correlated light beams to enhance the probability of detection of a partially reflecting object lying in a very noisy background. Recently a simple photon-number-detection-based implementation of a quantum illumination-like scheme was provided in Phys. Rev. Lett. 101, 153603 (2013), where the enhancement was preserved despite the loss of nonclassicality. In the present paper, we investigate the source for quantum advantage in that realization. We introduce an effective two-mode description of the light sources and analyze the mutual information (MI) as a quantifier of total correlations in the effective two-mode picture. In the relevant regime of a highly thermalized background, we find that the improvement in the signal-to-noise ratio achieved by the entangled sources over the unentangled thermal ones amounts exactly to the ratio of the effective MIs of the corresponding sources. More precisely, both quantities tend to a common limit specified by the squared ratio of the respective cross correlations. A thorough analysis of the experimental data confirms this theoretical result.

© 2014 Optical Society of America

OCIS Codes
(270.5570) Quantum optics : Quantum detectors
(270.6570) Quantum optics : Squeezed states
(270.5585) Quantum optics : Quantum information and processing

ToC Category:
Quantum Optics

Original Manuscript: April 4, 2014
Manuscript Accepted: June 23, 2014
Published: August 6, 2014

Sammy Ragy, Ivano Ruo Berchera, Ivo P. Degiovanni, Stefano Olivares, Matteo G. A. Paris, Gerardo Adesso, and Marco Genovese, "Quantifying the source of enhancement in experimental continuous variable quantum illumination," J. Opt. Soc. Am. B 31, 2045-2050 (2014)

Sort:  Author  |  Year  |  Journal  |  Reset  


  1. S. Lloyd, “Enhanced sensitivity of photodetection via quantum illumination,” Science 321, 1463–1465 (2008). [CrossRef]
  2. S.-H. Tan, B. I. Erkmen, V. Giovannetti, S. Guha, S. Lloyd, L. Maccone, S. Pirandola, and J. H. Shapiro, “Quantum illumination with Gaussian states,” Phys. Rev. Lett. 101, 253601 (2008). [CrossRef]
  3. T. Iskhakov, M. V. Chekhova, and G. Leuchs, “Generation and direct detection of broadband mesoscopic polarization-squeezed vacuum,” Phys. Rev. Lett. 102, 183602 (2009). [CrossRef]
  4. N. Thomas-Peter, B. J. Smith, A. Datta, L. Zhang, U. Dorner, and I. A. Walmsley, “Real-world quantum sensors: evaluating resources for precision measurement,” Phys. Rev. Lett. 107, 113603 (2011). [CrossRef]
  5. C. Weedbrook, S. Pirandola, R. Garcia-Patron, N. J. Cerf, T. C. Ralph, J. H. Shapiro, and S. Lloyd, “Gaussian quantum information,” Rev. Mod. Phys. 84, 621–669 (2012). [CrossRef]
  6. S. Olivares, “Quantum optics in the phase space: a tutorial on Gaussian states,” Eur. Phys. J. Spec. Top. 203, 3–24 (2012). [CrossRef]
  7. G. Adesso, S. Ragy, and A. Lee, “Continuous variable quantum information: Gaussian states and beyond,” Open Syst. Inf. Dyn. 21, 1440001 (2014). [CrossRef]
  8. Z. Y. Ou, S. F. Pereira, H. J. Kimble, and K. C. Peng, “Realization of the Einstein–Podolsky–Rosen paradox for continuous variables,” Phys. Rev. Lett. 68, 3663–3666 (1992). [CrossRef]
  9. J. Laurat, G. Keller, J. A. Oliveira-Huguenin, C. Fabre, T. Coudreau, A. Serafini, G. Adesso, and F. Illuminati, “Entanglement of two-mode Gaussian states: characterization and experimental production and manipulation,” J. Opt. B 7, S577–S587 (2005). [CrossRef]
  10. V. D’Auria, S. Fornaro, A. Porzio, S. Solimeno, S. Olivares, and M. G. A. Paris, “Full characterization of Gaussian bipartite entangled states by a single homodyne detector,” Phys. Rev. Lett. 102, 020502 (2009). [CrossRef]
  11. T. Eberle, V. Händchen, and R. Schnabel, “Stable control of 10  dB two-mode squeezed vacuum states of light,” Opt. Express 21, 11546 (2013). [CrossRef]
  12. S. Olivares and M. G. A. Paris, “Fidelity matters: the birth of entanglement in the mixing of Gaussian states,” Phys. Rev. Lett. 107, 170505 (2011). [CrossRef]
  13. K. M. R. Audenaert, J. Calsamiglia, R. Munoz-Tapia, E. Bagan, L. Masanes, A. Acin, and F. Verstraete, “Discriminating states: the quantum Chernoff bound,” Phys. Rev. Lett. 98, 160501 (2007). [CrossRef]
  14. S. Pirandola and S. Lloyd, “Computable bounds for the discrimination of Gaussian states,” Phys. Rev. A 78, 012331 (2008). [CrossRef]
  15. S. Guha and B. I. Erkmen, “Gaussian-state quantum-illumination receivers for target detection,” Phys. Rev. A 80, 052310 (2009). [CrossRef]
  16. E. D. Lopaeva, I. R. Berchera, I. P. Degiovanni, S. Olivares, G. Brida, and M. Genovese, “Experimental realization of quantum illumination,” Phys. Rev. Lett. 110, 153603 (2013). [CrossRef]
  17. Z. Zhang, M. Tengner, T. Zhong, F. N. C. Wong, and J. H. Shapiro, “Entanglement’s benefit survives an entanglement-breaking channel,” Phys. Rev. Lett. 111, 010501 (2013). [CrossRef]
  18. C. Weedbrook, S. Pirandola, J. Thompson, V. Vedral, and M. Gu, “Discord empowered quantum illumination,” arXiv:1312.3332 (2013).
  19. D. Girolami, A. M. Souza, V. Giovannetti, T. Tufarelli, J. G. Filgueiras, R. S. Sarthour, D. O. Soares-Pinto, I. S. Oliveira, and G. Adesso, “Quantum discord determines the interferometric power of quantum states,” Phys. Rev. Lett. 112, 210401 (2014). [CrossRef]
  20. G. Adesso, “Gaussian interferometric power,” arXiv:1406.5857 (2014).
  21. A. Farace, A. De Pasquale, L. Rigovacca, and V. Giovannetti, “Discriminating strength: a bona fide measure of non-classical correlations,” New J. Phys. 16, 073010 (2014).
  22. S. Ragy and G. Adesso, “Nature of light correlations in ghost imaging,” Sci. Rep. 2, 651 (2012). [CrossRef]
  23. G. Brida, M. Genovese, and I. Ruo-Berchera, “Experimental realization of sub-shot-noise quantum imaging,” Nat. Photonics 4, 227–230 (2010). [CrossRef]
  24. G. Brida, L. Caspani, A. Gatti, M. Genovese, A. Meda, and I. R. Berchera, “Measurement of sub-shot-noise spatial correlations without background subtraction,” Phys. Rev. Lett. 102, 213602 (2009). [CrossRef]
  25. A. Gatti, E. Brambilla, M. Bache, and L. A. Lugiato, “Correlated imaging, quantum and classical,” Phys. Rev. A 70, 013802 (2004). [CrossRef]
  26. S. Ragy is preparing a manuscript to be called “A Gaussian single mode approximation for multi-mode photon counting statistics.”
  27. G. Adesso and F. Illuminati, “Entanglement in continuous-variable systems: recent advances and current perspectives,” J. Phys. A Math. Theor. 40, 7821–7880 (2007). [CrossRef]
  28. A. Rényi, “On measures of entropy and information,” in Proceedings of the Fourth Berkeley Symposium on Mathematical Statistics and Probability (University of California, 1961), Vol. 1, pp. 547–561.
  29. G. Adesso, D. Girolami, and A. Serafini, “Measuring Gaussian quantum information and correlations using the Renyi entropy of order 2,” Phys. Rev. Lett. 109, 190502 (2012). [CrossRef]
  30. S. Ragy and G. Adesso, “Unveiling the Hanbury Brown and Twiss effect through Renyi entropy correlations,” Phys. Scr. T153, 014052 (2013). [CrossRef]
  31. E. D. Lopaeva, I. R. Berchera, S. Olivares, G. Brida, I. P. Degiovanni, and M. Genovese, “A detailed description of the experimental realisation of quantum illumination protocol,” Phys. Scr. T160, 014026 (2014). [CrossRef]
  32. M. Bondani, A. Allevi, G. Zambda, M. G. A. Paris, and A. Andreoni, “Sub-shot-noise photon-number correlation in a mesoscopic twin beam of light,” Phys. Rev. A 76, 013833 (2007). [CrossRef]
  33. T. Ishkakov, M. V. Checkhova, and G. Leuchs, “Generation and direct detection of broadband mesoscopic polarization-squeezed vacuum,” Phys. Rev. Lett. 102, 183602 (2009). [CrossRef]
  34. M. Gu, H. M. Chrzanowski, S. M. Assad, T. Symul, K. Modi, T. C. Ralph, V. Vedral, and P. K. Lam, “Observing the operational significance of discord consumption,” Nat. Phys. 8, 671–675 (2012). [CrossRef]

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.


Fig. 1. Fig. 2. Fig. 3.

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited