Abstract
We derive a Bell inequality for testing violation of local realism. Quantum nonlocality of several four-qubit states is investigated. These include the Greenberger-Zeilinger-Horne (GHZ) state, state, linear cluster state, and the state that has recently been proposed in [Phys. Rev. Lett. 96, 060502 (2006)]. The Bell inequality is optimally violated by but not violated by the GHZ state. The linear cluster state also violates the Bell inequality though not optimally. The state can thus be discriminated from the linear cluster state by using the inequality. Different aspects of four-partite entanglement are also studied by considering the usefulness of a family of four-qubit mixed states as resources for two-qubit teleportation. Our results generalize those in [Phys. Rev. Lett. 72, 797 (1994)].
- Received 17 November 2006
DOI:https://doi.org/10.1103/PhysRevA.75.032332
©2007 American Physical Society