Multiparticle covariance matrices and the impossibility of detecting graph-state entanglement with two-particle correlations

Journal Article · Wed Sep 15 04:00:00 EDT 2010 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.82.032306· OSTI ID:21448645

Gittsovich, Oleg ^[1]; Hyllus, Philipp ^[2]; Guehne, Otfried ^[3]

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1. Institute for Quantum Computing, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1 (Canada)
2. INO-CNR BEC Center and Dipartimento di Fisica, Universita di Trento, I-38123 Povo (Italy)
3. Institut fuer Quantenoptik und Quanteninformation, Oesterreichische Akademie der Wissenschaften, Otto-Hittmair-Platz 1, 6020 Innsbruck (Austria)

We present a criterion for multiparticle entanglement based on covariance matrices. On the one hand, the criterion allows detection of bound entangled states which are not detected by other criteria; on the other hand, some strongly entangled pure states such as the Greenberger-Horne-Zeilinger (GHZ) states are not detected. We show, however, that this is a general phenomenon: No separability criterion based on two-particle correlations can recognize the entanglement in the family of graph states to which the GHZ states belong.

• OSTI ID: 21448645
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 3 Vol. 82; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BOUND STATE
CORRELATIONS
DETECTION
FREQUENCY RANGE
GHZ RANGE
MATRICES
MECHANICS
PURE STATES
QUANTUM ENTANGLEMENT
QUANTUM MECHANICS
QUANTUM STATES