Erlangen 2018 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 56: Quantum Information (Coherence and Entanglement)

Q 56.8: Talk

Thursday, March 8, 2018, 12:15–12:30, K 1.019

Unitary designs for reference-frame independent entanglement detection — •Andreas Ketterer, Nikolai Wyderka, and Otfried Gühne — Universität Siegen, Siegen, Germany

The trustworthy detection of multipartite entanglement usually requires a number judiciously chosen local quantum measurements which are aligned with respect to a previously shared common reference frame. If such a reference frame is not available one has to develop alternative detection strategies which do not rely on a specific choice of the local measurement bases. One possibility in this direction is to perform a number of local measurements with settings distributed uniformly at random. Using such a statistical treatment we show that one can make use of quantum unitary designs to derive reference frame independent multi-qubit entanglement criteria based on the first six moments of the randomly measured expectation values. We illustrate our method in the case of a bipartite system where it allows for a characterization of all entangled Bell diagonal states. Subsequently, we move to the more involved multipartite scenario and show how to detect multi-qubit entanglement from two-body correlations.