title: Taming multiparticle entanglement.
abstract: We present an approach to characterize genuine multiparticle entanglement by using appropriate approximations in the space of quantum states. This leads to a criterion for entanglement which can easily be calculated by using semidefinite programing and improves all existing approaches significantly. Experimentally, it can also be evaluated when only some observables are measured. Furthermore, it results in a computable entanglement monotone for genuine multiparticle entanglement. Based on this, we develop an analytical approach for the entanglement detection in cluster states, leading to an exponential improvement compared with existing schemes.
authors.affiliation: Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Technikerstraße 21A, A-6020 Innsbruck, Austria.
authors.forename: Bastian
authors.initials: B
authors.lastname: Jungnitsch
authors.forename: Tobias
authors.initials: T
authors.lastname: Moroder
authors.forename: Otfried
authors.initials: O
authors.lastname: Gühne