Entanglement of Three-Qubit Greenberger-Horne-Zeilinger–Symmetric States
Entanglement of Three-Qubit Greenberger-Horne-Zeilinger–Symmetric States
The first characterization of mixed-state entanglement was achieved for two-qubit states in Werner's seminal work [Phys. Rev. A 40, 4277 (1989)]. A physically important extension of this result concerns mixtures of a pure entangled state (such as the Greenberger-Horne-Zeilinger [GHZ] state) and the completely unpolarized state. These mixed states serve …