We derive reliable entanglement witnesses for coarse--grained measurements on continuous variable systems. These witnesses never return a "false positive" for identification of entanglement, under any degree of coarse graining. We show that, even in the case of Gaussian states, entanglement witnesses based on the Shannon entropy can outperform those based on variances. We apply our results to experimental identification of spatial entanglement of photon pairs.
@article{arxiv.1210.5945,
title = {Reliable Entanglement Detection Under Coarse--Grained Measurements},
author = {D. S. Tasca and Łukasz Rudnicki and R. M. Gomes and F. Toscano and S. P. Walborn},
journal= {arXiv preprint arXiv:1210.5945},
year = {2013}
}
Comments
Dedicated to Iwo Bialynicki-Birula on his 80th birthday, who inspired much of this work