Monogamy inequality in terms of negativity for three-qubit states

Jun 8, 2007
5 pages
Published in:
  • Phys.Rev.A 75 (2007) 6, 062308
  • Published: Jun 8, 2007

Citations per year

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Abstract: (APS)
We propose an entanglement measure to quantify three-qubit entanglement in terms of negativity. A monogamy inequality analogous to the Coffman-Kundu-Wootters inequality is established. This consequently leads to a definition of residual entanglement, which is referred to as the three-\ensuremath{\pi} in order to distinguish it from the three-tangle. The three-\ensuremath{\pi} is proved to be a natural entanglement measure. By contrast to the three-tangle, it is shown that the three-\ensuremath{\pi} always gives greater than zero values for pure states belonging to the WW and Greenberger-Horne-Zeilinger classes, implying that three-way entanglement always exists for them; the three-tangle generally underestimates the three-way entanglement of a given system. This investigation will offer an alternative tool to understand genuine multipartite entanglement.
  • entanglement
  • pure state
  • quantum state
  • qubit
  • 03.67.Mn
  • 03.65.Ud
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