# Quantum nonlocality of four-qubit entangled states

## 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, W state, linear cluster state, and the state |{chi}> that has recently been proposed in [Phys. Rev. Lett. 96, 060502 (2006)]. The Bell inequality is optimally violated by |{chi}> but not violated by the GHZ state. The linear cluster state also violates the Bell inequality though not optimally. The state |{chi}> 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)].

- Authors:

- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore)
- (Singapore)

- Publication Date:

- OSTI Identifier:
- 20982278

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Physical Review. A; Journal Volume: 75; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevA.75.032332; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; BELL THEOREM; QUANTUM COMPUTERS; QUANTUM ENTANGLEMENT; QUANTUM MECHANICS; QUANTUM TELEPORTATION; QUBITS; TESTING

### Citation Formats

```
Wu, Chunfeng, Yeo, Ye, Oh, C. H., Kwek, L. C., and Nanyang Technological University, National Institute of Education, 1 Nanyang Walk, Singapore 637616.
```*Quantum nonlocality of four-qubit entangled states*. United States: N. p., 2007.
Web. doi:10.1103/PHYSREVA.75.032332.

```
Wu, Chunfeng, Yeo, Ye, Oh, C. H., Kwek, L. C., & Nanyang Technological University, National Institute of Education, 1 Nanyang Walk, Singapore 637616.
```*Quantum nonlocality of four-qubit entangled states*. United States. doi:10.1103/PHYSREVA.75.032332.

```
Wu, Chunfeng, Yeo, Ye, Oh, C. H., Kwek, L. C., and Nanyang Technological University, National Institute of Education, 1 Nanyang Walk, Singapore 637616. Thu .
"Quantum nonlocality of four-qubit entangled states". United States.
doi:10.1103/PHYSREVA.75.032332.
```

```
@article{osti_20982278,
```

title = {Quantum nonlocality of four-qubit entangled states},

author = {Wu, Chunfeng and Yeo, Ye and Oh, C. H. and Kwek, L. C. and Nanyang Technological University, National Institute of Education, 1 Nanyang Walk, Singapore 637616},

abstractNote = {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, W state, linear cluster state, and the state |{chi}> that has recently been proposed in [Phys. Rev. Lett. 96, 060502 (2006)]. The Bell inequality is optimally violated by |{chi}> but not violated by the GHZ state. The linear cluster state also violates the Bell inequality though not optimally. The state |{chi}> 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)].},

doi = {10.1103/PHYSREVA.75.032332},

journal = {Physical Review. A},

number = 3,

volume = 75,

place = {United States},

year = {Thu Mar 15 00:00:00 EDT 2007},

month = {Thu Mar 15 00:00:00 EDT 2007}

}