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Many-region vacuum entanglement: Distilling a W state

J. Silman·B. Reznik
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Abstract

We investigate the correlations between any number of arbitrarily far-apart regions of the vacuum of the free Klein-Gordon field by means of its finite duration coupling to an equal number of localized detectors. We show that the correlations between any N such regions enable us to distill an N-partite W state, and therefore exhibit true $N$-fold entanglement. Furthermore, we show that for N=3, the correlations cannot be reproduced by a hybrid local-nonlocal hidden-variable model. For N >= 4 the issue remains open.

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J. Silman, B. Reznik. 2005-08-10. Many-region vacuum entanglement: Distilling a W state. https://doi.org/10.1103/physreva.71.054301

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