title: Reliable entanglement detection under coarse-grained measurements.
abstract: 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.
authors.affiliation: SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom.
authors.forename: D S
authors.initials: DS
authors.lastname: Tasca
authors.forename: Łukasz
authors.initials: Ł
authors.lastname: Rudnicki
authors.forename: R M
authors.initials: RM
authors.lastname: Gomes
authors.forename: F
authors.initials: F
authors.lastname: Toscano
authors.forename: S P
authors.initials: SP
authors.lastname: Walborn