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arXiv · 1908.04220

Maximum $N$-body correlations do not in general imply genuine multipartite entanglement

Christopher Eltschka·Jens Siewert
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Abstract

The existence of correlations between the parts of a quantum system on the one hand, and entanglement between them on the other, are different properties. Yet, one intuitively would identify strong $N$-party correlations with $N$-party entanglement in an $N$-partite quantum state. If the local systems are qubits, this intuition is confirmed: The state with the strongest $N$-party correlations is the Greenberger-Horne-Zeilinger (GHZ) state, which does have genuine multipartite entanglement. However, for high-dimensional local systems the state with strongest $N$-party correlations may be a tensor product of Bell states, that is, partially separable. We show this by introducing several novel tools for handling the Bloch representation.

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Christopher Eltschka, Jens Siewert. 2019-08-12. Maximum $N$-body correlations do not in general imply genuine multipartite entanglement. https://doi.org/10.22331/q-2020-02-10-229

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