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Q: Fachverband Quantenoptik und Photonik

Q 46: Quantum information: Concepts and methods IV

Q 46.4: Talk

Thursday, March 21, 2013, 11:45–12:00, E 001

A quantitative witness for Greenberger-Horne-Zeilinger entanglement — •Christopher Eltschka¹ and Jens Siewert^2,3 — ¹Institut für Theoretische Physik, Universität Regensburg, D-93040 Regensburg, Germany — ²Departamento de Química Física, Universidad del País Vasco UPV/EHU, 48080 Bilbao, Spain — ³IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain

Along with the vast progress in experimental quantum technologies there is an increasing demand for the quantification of entanglement between three or more quantum systems. Theory still does not provide adequate tools for this purpose. We provide a simple procedure to quantify Greenberger-Horne-Zeilinger-type multipartite entanglement in arbitrary three-qubit states [1]. The method is based on the recently introduced GHZ symmetry [2] and exact results for the states which are invariant under this symmetry [3], and generally gives a good lower bound to the three-tangle. A generalization both to more parties and to higher-dimensional systems is possible.

[1] C. Eltschka, J. Siewert. Sci. Rep. 2, 942 (2012)

[2] C. Eltschka, J. Siewert, PRL 108, 020502 (2012)

[3] J. Siewert, C. Eltschka, PRL 108, 230502 (2012)