Quantumness of correlations, quantumness of ensembles and quantum data hiding

Marco Piani, Varun Narasimhachar, John Calsamiglia

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

We study the quantumness of correlations for ensembles of bi- and multi-partite systems and relate it to the task of quantum data hiding. Quantumness is here intended in the sense of minimum average disturbance under local measurements. We consider a very general framework, but focus on local complete von Neumann measurements as cause of the disturbance, and, later on, on the trace-distance as quantifier of the disturbance. We discuss connections with entanglement and previously defined notions of quantumness of correlations. We prove that a large class of quantifiers of the quantumness of correlations are entanglement monotones for pure bipartite states. In particular, we define an entanglement of disturbance for pure states, for which we give an analytical expression. Such a measure coincides with negativity and concurrence for the case of two qubits. We compute general bounds on disturbance for both single states and ensembles, and consider several examples, including the uniform Haar ensemble of pure states, and pairs of qubit states. Finally, we show that the notion of ensemble quantumness of correlations is most relevant in quantum data hiding. Indeed, while it is known that entanglement is not necessary for a good quantum data hiding scheme, we prove that ensemble quantumness of correlations is.
LanguageEnglish
Article number113001
Number of pages33
JournalNew Journal of Physics
Volume16
Issue number11
DOIs
Publication statusPublished - 31 Oct 2014

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Keywords

  • von Neumann measurement
  • correlations
  • quantum data hiding

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Piani, Marco ; Narasimhachar, Varun ; Calsamiglia, John. / Quantumness of correlations, quantumness of ensembles and quantum data hiding. In: New Journal of Physics. 2014 ; Vol. 16, No. 11.
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Quantumness of correlations, quantumness of ensembles and quantum data hiding. / Piani, Marco; Narasimhachar, Varun; Calsamiglia, John.

In: New Journal of Physics, Vol. 16, No. 11, 113001, 31.10.2014.

Research output: Contribution to journalArticle

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