Channel discrimination power of bipartite quantum states

Matteo Caiaffa, Marco Piani

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Abstract

We quantify the usefulness of a bipartite quantum state in the ancilla-assisted channel discrimination of arbitrary quantum channels, formally defining a worst-case-scenario channel discrimination power for bipartite quantum states. We show that such a quantifier is deeply connected with the operator Schmidt decomposition of the state. We compute the channel discrimination power exactly for pure states, and provide upper and lower bounds for general mixed states. We show that highly entangled states can outperform any state that passes the realignment criterion for separability. Furthermore, while also unentangled states can be used in ancilla-assisted channel discrimination, we show that the channel discrimination power of a state is bounded by its quantum discord.
Original languageEnglish
Article number032334
Number of pages9
JournalPhysical Review A - Atomic, Molecular, and Optical Physics
Volume97
Issue number3
DOIs
Publication statusPublished - 23 Mar 2018

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Keywords

  • bipartite quantum states
  • quantum channel
  • channel discrimination

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