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Title: Purified discord and multipartite entanglement

We study bipartite quantum discord as a manifestation of a multipartite entanglement structure in the tripartite purified system. In particular, we find that bipartite quantum discord requires the presence of both bipartite and tripartite entanglement in the purification. This allows one to understand the asymmetry of quantum discord, D(A,B)≠D(B,A) in terms of entanglement monogamy. As instructive special cases, we study discord for qubits and Gaussian states in detail. As a result of this we shed new light on a counterintuitive property of Gaussian states: the presence of classical correlations necessarily requires the presence of quantum correlations. Finally, our results also shed new light on a protocol for remote activation of entanglement by a third party. -- Highlights: •Bipartite quantum discord as a manifestation of multipartite entanglement. •Relevance of quantum discord as a utilizable resource for quantum info. tasks. •Quantum discord manifests itself in entanglement in the purified state. •Relation between asymmetry of discord and entanglement monogamy. •Protocol for remote activation of entanglement by a third party.
Authors:
 [1] ;  [2] ;  [2] ;  [3] ;  [3] ;  [1] ;  [3] ;  [3] ;  [3] ;  [4]
  1. Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada)
  2. Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada)
  3. (Canada)
  4. (Australia)
Publication Date:
OSTI Identifier:
22224218
Resource Type:
Journal Article
Resource Relation:
Journal Name: Annals of Physics (New York); Journal Volume: 337; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ASYMMETRY; CORRELATIONS; QUANTUM ENTANGLEMENT; QUBITS