Hannover 2010 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 11: Quantum Information: Concepts and Methods II
Q 11.4: Talk
Monday, March 8, 2010, 17:15–17:30, E 214
Structure factors and entanglement witnesses — •Hermann Kampermann1, Philipp Krammer2, Dagmar Bruß1, Reinhold A. Bertlmann2, Leong Chuang Kwek3, and Chiara Macchiavello4 — 1Institut für Theoretische Physik III, Heinrich-Heine-Universität Düsseldorf — 2Faculty of Physics, University of Vienna, Austria — 3Centre for Quantum Technologies, National University of Singapore, Singapore — 4Dipartimento di Fisica ``A. Volta'', University of Pavia, Italy
We construct multi-qubit entanglement witnesses whose expectation value has a direct link to the static structure factor, and thus to diffractive properties. These ``collective'' witness operators are composed of two-point correlation operators. The general construction of these witnesses allows to detect different classes of multi-partite entangled states like Dicke states. The robustness of the entanglement detection with respect to noise is discussed.