Potential capacities of quantum channels

Andreas Winter, Dong Yang

Research output: Contribution to journalArticleResearchpeer-review

15 Citations (Scopus)

Abstract

© 2016 IEEE. We introduce potential capacities of quantum channels in an operational way and provide upper bounds for these quantities, which quantify the ultimate limit of usefulness of a channel for a given task in the best possible context. Unfortunately, except for a few isolated cases, potential capacities seem to be as hard to compute as their plain analogues. We thus study upper bounds on some potential capacities. For the classical capacity, we give an upper bound in terms of the entanglement of formation. To establish a bound for the quantum and private capacity, we first lift the channel to a Hadamard channel and then prove that the quantum and private capacity of a Hadamard channel is strongly additive, implying that for these channels, potential and plain capacity are equal. Employing these upper bounds, we show that if a channel is noisy, however close it is to the noiseless channel, then it cannot be activated into the noiseless channel by any other contextual channel; this conclusion holds for all the three capacities. We also discuss the so-called environment-assisted quantum capacity, because we are able to characterize its potential version.
Original languageEnglish
Article number7389396
Pages (from-to)1415-1424
JournalIEEE Transactions on Information Theory
Volume62
Issue number3
DOIs
Publication statusPublished - 1 Mar 2016

Keywords

  • entanglement
  • Hadamard channel
  • nonadditivity
  • potential capacity
  • quantum channel

Fingerprint Dive into the research topics of 'Potential capacities of quantum channels'. Together they form a unique fingerprint.

Cite this