title: Experimental entangled entanglement.
abstract: All previous tests of local realism have studied correlations between single-particle measurements. In the present experiment, we have performed a Bell experiment on three particles in which one of the measurements corresponds to a projection onto a maximally entangled state. We show theoretically and experimentally that correlations between these entangled measurements and single-particle measurements are too strong for any local-realistic theory and are experimentally exploited to violate a Clauser-Horne-Shimony-Holt-Bell inequality by more than 5 standard deviations. We refer to this possibility as "entangled entanglement."
authors.affiliation: Institut für Experimentalphysik, Universität Wien, Boltzmanngasse 5, A-1090 Wien, Austria.
authors.forename: Philip
authors.initials: P
authors.lastname: Walther
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Resch
authors.forename: Caslav
authors.initials: C
authors.lastname: Brukner
authors.forename: Anton
authors.initials: A
authors.lastname: Zeilinger