Quantumness of correlations, quantumness of ensembles and quantum data hiding
Piani, Marco (University of Strathclyde. Department of Physics)
Narasimhachar, Varun (University of Calgary. Department of Physics and Astronomy.)
Calsamiglia Costa, John (Universitat Autònoma de Barcelona. Departament de Física)

Date:	2014
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 the cause of the disturbance, and, later on, on the trace-distance as a 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 necessary.
Grants:	Ministerio de Economía y Competitividad FIS2008-01236
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Quantumness ; Discord ; Entanglement ; Disturbance ; Data hiding ; Ensemble
Published in:	New journal of physics, Vol. 16 (November 2014) , art. 113001, ISSN 1367-2630

DOI: 10.1088/1367-2630/16/11/113001

34 p, 869.4 KB

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