title: Detection of entanglement in asymmetric quantum networks and multipartite quantum steering.
abstract: The future of quantum communication relies on quantum networks composed by observers sharing multipartite quantum states. The certification of multipartite entanglement will be crucial to the usefulness of these networks. In many real situations it is natural to assume that some observers are more trusted than others in the sense that they have more knowledge of their measurement apparatuses. Here we propose a general method to certify all kinds of multipartite entanglement in this asymmetric scenario and experimentally demonstrate it in an optical experiment. Our results, which can be seen as a definition of genuine multipartite quantum steering, give a method to detect entanglement in a scenario in between the standard entanglement and fully device-independent scenarios, and provide a basis for semi-device-independent cryptographic applications in quantum networks.
authors.affiliation: ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, Avenue Carl Friedrich Gauss, 3, Castelldefels, 08860, Barcelona, Spain.
authors.forename: D
authors.initials: D
authors.lastname: Cavalcanti
authors.affiliation: ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, Avenue Carl Friedrich Gauss, 3, Castelldefels, 08860, Barcelona, Spain.|H. H. Wills Physics Laboratory, Tyndall Avenue, University of Bristol, Bristol BS8 1TL, UK.
authors.forename: P
authors.initials: P
authors.lastname: Skrzypczyk
authors.affiliation: Instituto de Fsica, Universidade Federal do Rio de Janeiro, CP 68528, 21941-972 Rio de Janeiro, Brazil.
authors.forename: G H
authors.initials: GH
authors.lastname: Aguilar
authors.affiliation: Instituto de Fsica, Universidade Federal do Rio de Janeiro, CP 68528, 21941-972 Rio de Janeiro, Brazil.
authors.forename: R V
authors.initials: RV
authors.lastname: Nery
authors.affiliation: Instituto de Fsica, Universidade Federal do Rio de Janeiro, CP 68528, 21941-972 Rio de Janeiro, Brazil.
authors.forename: P H Souto
authors.initials: PHS
authors.lastname: Ribeiro
authors.affiliation: Instituto de Fsica, Universidade Federal do Rio de Janeiro, CP 68528, 21941-972 Rio de Janeiro, Brazil.
authors.forename: S P
authors.initials: SP
authors.lastname: Walborn