Bit threshold optimization for multiphoton communication in lossy channels
- 34 Downloads
We address M-ary communication channels based on entangled two-mode states of radiation in the presence of losses. In particular we focus on channels build by two-mode coherently-correlated (TMC) or twin-beam (TWB) states. Optimized bit discrimination thresholds, as well as the corresponding maximized mutual information, are explicitly evaluated as a function of beam intensities and loss parameters for binary and quaternary alphabets. The evolution of the two entangled support states in lossy channels is analyzed and the joint photon number distribution is evaluated, showing that the beam statistics (either sub-Poissonian for TMC or super-Poissonian for TWB) is not altered by channel losses. The effects of losses on the channel security is discussed.
Unable to display preview. Download preview PDF.
- 2.C. H. Bennett and G. Brassard, in Proceedings of the IEEE International Conference on Computers, Systems and Signal Processing, Bangalore, India (IEEE, New York, 1984), pp. 175–179.Google Scholar
- 4.W. Tittel and G. Weihs, Quantum. Inf. Comp. 1(2), 3 (2001); quant-ph/0107156.Google Scholar
- 5.L. Mandel and E. Wolf, Optical Coherence and Quantum Optics (Cambridge Univ. Press, 1995), pp. 816–827Google Scholar
- 7.D. F. Walls and G. J. Milburn, in Quantum Optics (Springer, New York, 1995), pp. 146–157Google Scholar
- 9.J. Laurat, T. Coudreau, N. Treps, et al., Phys. Rev. Lett. 91, 213601 (2003); quant-ph/03040.Google Scholar
- 10.J. Perina, Jr., O. Haderka, M. Hamar, and J. Perina, Phys. Rev. A 71, 033815 (2005); quant-ph/0405118.Google Scholar
- 17.V. C. Usenko and C. V. Usenko, in Proceedings of the Seventh International Conference on Quantum Communication, Measurement and Computing, Glasgow, UK, 2004 (AIP, Boston, 2004), Vol. CP734, p. 319; quant-ph/0407175.Google Scholar