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arXiv · 1412.5881

Multipartite entanglement detection with minimal effort

Lukas Knips·Christian Schwemmer·Nico Klein·Marcin Wieśniak·Harald Weinfurter
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Abstract

Certifying entanglement of a multipartite state is generally considered as a demanding task. Since an $N$ qubit state is parametrized by $4^{N}-1$ real numbers, one might naively expect that the measurement effort of generic entanglement detection also scales exponentially with $N$. Here, we introduce a general scheme to construct efficient witnesses requiring a constant number of measurements independent of the number of qubits for states like, e.g., Greenberger-Horne-Zeilinger states, cluster states and Dicke states. For four qubits, we apply this novel method to experimental realizations of the aforementioned states and prove genuine four-partite entanglement with two measurement settings only.

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Lukas Knips, Christian Schwemmer, Nico Klein, Marcin Wieśniak, Harald Weinfurter. 2016-10-06. Multipartite entanglement detection with minimal effort. https://doi.org/10.1103/physrevlett.117.210504

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