Entanglement swapping of noisy states: A kind of superadditivity in nonclassicality
- Instytut Fizyki Teoretycznej i Astrofizyki, Uniwersytet Gdanski, PL-80-952 Gdansk (Poland)
- Institut fuer Experimentalphysik, Universitaet Wien, Boltzmanngasse 5, A-1090 (Austria)
- Research Center for Quantum Information, Slovak Academy of Sciences, Dubravska cesta 9, 845 11 Bratislava (Slovakia)
We address the question as to whether an entangled state that satisfies local realism will give a violation of the same after entanglement swapping in a suitable scenario. We consider such a possibility as a kind of superadditivity in nonclassicality. Importantly, it will indicate that checking for violation of local realism, in the state obtained after entanglement swapping, can be a method for detecting entanglement in the input state of the swapping procedure. We investigate various entanglement swapping schemes, which involve mixed initial states. The strength of violation of local realism by the state obtained after entanglement swapping is compared with the one for the input states. We obtain a kind of superadditivity of violation of local realism for Werner states, consequent upon entanglement swapping involving Greenberger-Horne-Zeilinger-state measurements. We also discuss whether entanglement swapping of specific states may be used in quantum repeaters with a substantially reduced need to perform the entanglement distillation step.
- OSTI ID:
- 20718703
- Journal Information:
- Physical Review. A, Vol. 72, Issue 4; Other Information: DOI: 10.1103/PhysRevA.72.042310; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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