# Witnessing nonclassical multipartite states

@article{Saguia2011WitnessingNM, title={Witnessing nonclassical multipartite states}, author={Andreia Saguia and Clodoaldo Cordeiro Rulli and Thiago. R. de Oliveira and Marcelo S. Sarandy}, journal={Physical Review A}, year={2011}, volume={84} }

We investigate a witness for nonclassical multipartite states based on their disturbance under local measurements. The witness operator provides a sufficient condition for nonclassicality that coincides with a nonvanishing global quantum discord, but it does not demand an extremization procedure. Moreover, for the case of Z{sub 2}-symmetric systems, we rewrite the witness in terms of correlation functions so that classicality is found to necessarily require either vanishing magnetization in the… Expand

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