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arXiv · 1811.09896

Entanglement Witness $2.0$: Compressed/Mirrored Entanglement Witnesses

Joonwoo Bae·Dariusz Chruściński·Beatrix C. Hiesmayr
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Abstract

An entanglement witness is an observable detecting entanglement for a subset of states. We present a framework that makes an entanglement witness twice as powerful due to the general existence of a second (lower) bound, in addition to the (upper) bound of the very definition. This second bound, if non-trivial, is violated by another subset of entangled states. Differently stated, we prove via the structural physical approximation that two witnesses can be compressed into a single one. Consequently, our framework shows that any entanglement witness can be upgraded to a witness $2.0$. The generality and its power are demonstrate by applications to bipartite and multipartite qubit/qudit systems.

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Joonwoo Bae, Dariusz Chruściński, Beatrix C. Hiesmayr. 2018-11-24. Entanglement Witness $2.0$: Compressed/Mirrored Entanglement Witnesses. https://doi.org/10.1038/s41534-020-0242-z

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