Capacity bounds via operator space methods

Li Gao, Marius Junge, Nicholas Laracuente

Research output: Contribution to journalArticlepeer-review


We prove that for generalized dephasing channels, the coherent information and reverse coherent information coincides. It also implies an alternative approach for the strong super-additivity and strong converse of generalized dephasing channels using the operator space technique. Our argument is based on an improved Rényi relative entropy estimate via analyzing the channel's Stinespring space. We also apply this estimate to new examples of quantum channels arising from quantum group co-representation and Kitave's quantum computation model. In particular, we find concrete examples of non-degradable channels that our estimates are tight and give a formula of nontrivial quantum capacity.

Original languageEnglish (US)
Article number122202
JournalJournal of Mathematical Physics
Issue number12
StatePublished - Dec 1 2018

ASJC Scopus subject areas

  • Statistical and Nonlinear Physics
  • Mathematical Physics


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