Entanglement swapping of noisy states: A kind of superadditivity in nonclassicality

Author(s): Aditi Sen, Ujjwal Sen, Caslav Brukner, Vladimir Buzek, Marek Zukowski
Abstract: 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. Œ 2005 The American Physical Society.
Organisation(s)
External organisation(s): University of Gdańsk, Masaryk University
Journal: Physical Review A
Volume: 72
No. of pages: 10
ISSN: 1050-2947
DOI: https://doi.org/10.1103/PhysRevA.72.042310
Publication date: 2005
Peer reviewed: Yes
Austrian Fields of Science 2012: 103026 Quantum optics
Portal url: https://ucrisportal.univie.ac.at/en/publications/467d721d-084a-40a8-9c46-2f2909400ea2