A counterexample to additivity of minimum output entropy

  title={A counterexample to additivity of minimum output entropy},
  author={Matthew B. Hastings},
  journal={Physical Review Letters},
  • M. Hastings
  • Published 23 September 2008
  • Mathematics
  • Physical Review Letters
We present a random construction of a pair of channels which gives, with non-zero probability for sufficiently large dimensions, a counterexample to the minimum output entropy conjecture. As shown by Shor, this implies a violation of the additivity conjecture for the classical capacity of quantum channels. The violation of the minimum output entropy conjecture is relatively small. 
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