Positivity and Nonadditivity of Quantum Capacities Using Generalized Erasure Channels

  title={Positivity and Nonadditivity of Quantum Capacities Using Generalized Erasure Channels},
  author={Vikesh Siddhu and Robert B. Griffiths},
  journal={IEEE Transactions on Information Theory},
We consider various forms of a process, which we call <italic>gluing</italic>, for combining two or more complementary quantum channel pairs <inline-formula> <tex-math notation="LaTeX">$({\mathcal B}, {\mathcal C})$ </tex-math></inline-formula> to form a composite. One type of gluing combines a perfect channel with a second channel to produce a <italic>generalized erasure channel</italic> pair <inline-formula> <tex-math notation="LaTeX">$({\mathcal B}_{g}, {\mathcal C}_{g})$ </tex-math></inline… 

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