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Title: Entanglement, EPR steering, and Bell-nonlocality criteria for multipartite higher-spin systems

Journal Article · · Physical Review. A
; ;  [1]
  1. ARC Centre of Excellence for Quantum-Atom Optics, Centre for Atom Optics and Ultrafast Spectroscopy, Swinburne University of Technology, Melbourne 3122 (Australia)

We develop criteria to detect three classes of nonlocality that have been shown by Wiseman et al. [Phys. Rev. Lett. 98, 140402 (2007)] to be nonequivalent: entanglement, EPR steering, and the failure of local hidden-variable theories. We use the approach of Cavalcanti et al. [Phys. Rev. Lett. 99, 210405 (2007)] for continuous variables to develop the nonlocality criteria for arbitrary spin observables defined on a discrete Hilbert space. The criteria thus apply to multisite qudits, i.e., systems of fixed dimension d, and take the form of inequalities. We find that the spin moment inequalities that test local hidden variables (Bell inequalities) can be violated for arbitrary d by optimized highly correlated nonmaximally entangled states provided the number of sites N is high enough. On the other hand, the spin inequalities for entanglement are violated and thus detect entanglement for such states, for arbitrary d and N, and with a violation that increases with N. We show that one of the moment entanglement inequalities can detect the entanglement of an arbitrary generalized multipartite Greenberger-Horne-Zeilinger state. Because they involve the natural observables for atomic systems, the relevant spin-operator correlations should be readily observable in trapped ultracold atomic gases and ion traps.

OSTI ID:
21537392
Journal Information:
Physical Review. A, Vol. 83, Issue 3; Other Information: DOI: 10.1103/PhysRevA.83.032120; (c) 2011 American Institute of Physics; ISSN 1050-2947
Country of Publication:
United States
Language:
English