Strong Converse for the Classical Capacity of Optical Quantum Communication Channels

Bhaskar Roy Bardhan, Raul Garcia-Patron Sanchez, Mark M. Wilde, Andreas Winter

Research output: Contribution to journalArticlepeer-review


We establish the classical capacity of optical quantum channels as a sharp transition between two regimes-one which is an error-free regime for communication rates below the capacity, and the other in which the probability of correctly decoding a classical message converges exponentially fast to zero if the communication rate exceeds the classical capacity. This result is obtained by proving a strong converse theorem for the classical capacity of all phase-insensitive bosonic Gaussian channels, a well-established model of optical quantum communication channels, such as lossy optical fibers, amplifier, and free-space communication. The theorem holds under a particular photon-number occupation constraint, which we describe in detail in this paper. Our result bolsters the understanding of the classical capacity of these channels and opens the path to applications, such as proving the security of noisy quantum storage models of cryptography with optical links.
Original languageEnglish
Pages (from-to)1842-1850
Number of pages9
JournalIEEE Transactions on Information Theory
Issue number4
Early online date13 Feb 2015
Publication statusPublished - 30 Apr 2015


  • decoding
  • Gaussian channels
  • optical links
  • quantum cryptography
  • optical quantum communication channels
  • classical capacity
  • error-free regime
  • communication rates
  • correctly decoding probability
  • classical message
  • strong converse theorem
  • all phase-insensitive bosonic Gaussian channels
  • optical fibers
  • optical amplifier
  • free-space communication
  • photon-number occupation constraint
  • noisy quantum storage models
  • cryptography
  • Photonics
  • Entropy
  • Niobium
  • Thermal noise
  • Capacity planning
  • Channel capacity
  • Elementary particle vacuum
  • channel capacity
  • Gaussian quantum channels
  • optical communication channels
  • photon number constraint


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