Multiparticle covariance matrices and the impossibility of detecting graph state entanglement with two-particle correlations
Quantum Physics
2010-09-13 v1
Abstract
We present a criterion for multiparticle entanglement based on covariance matrices. On the one hand, the criterion allows to detect bound entangled states which are not detected by other criteria; on the other hand, some strongly entangled pure states such as the GHZ states are not detected. We show, however, that this is a general phenomenon: No separability criterion based on two-particle correlations can recognize the entanglement in the family of graph states, to which the GHZ states belong.
Keywords
Cite
@article{arxiv.1006.1594,
title = {Multiparticle covariance matrices and the impossibility of detecting graph state entanglement with two-particle correlations},
author = {Oleg Gittsovich and Philipp Hyllus and Otfried Gühne},
journal= {arXiv preprint arXiv:1006.1594},
year = {2010}
}
Comments
10 pages, 3 figures