title: 14-Qubit entanglement: creation and coherence.
abstract: We report the creation of Greenberger-Horne-Zeilinger states with up to 14 qubits. By investigating the coherence of up to 8 ions over time, we observe a decay proportional to the square of the number of qubits. The observed decay agrees with a theoretical model which assumes a system affected by correlated, Gaussian phase noise. This model holds for the majority of current experimental systems developed towards quantum computation and quantum metrology.
authors.affiliation: Institut für Experimentalphysik, Universität Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Monz
authors.forename: Philipp
authors.initials: P
authors.lastname: Schindler
authors.forename: Julio T
authors.initials: JT
authors.lastname: Barreiro
authors.forename: Michael
authors.initials: M
authors.lastname: Chwalla
authors.forename: Daniel
authors.initials: D
authors.lastname: Nigg
authors.forename: William A
authors.initials: WA
authors.lastname: Coish
authors.forename: Maximilian
authors.initials: M
authors.lastname: Harlander
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Hänsel
authors.forename: Markus
authors.initials: M
authors.lastname: Hennrich
authors.forename: Rainer
authors.initials: R
authors.lastname: Blatt