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arXiv · 1512.06010

The fourtangle in the transverse XY model

Andreas Osterloh·Ralf Schützhold
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Abstract

We analyze the entanglement measure $C_4$ for mixed states in general and for the transverse XY model. We come to the conclusion that it cannot serve alone for guaranteeing an entanglement of $GHZ_4$-type. The genuine negativity calculated in Ref.~\cite{Hofmann14} isn't sufficient for that either and some additional measure of entanglement must be considered. In particular we study the transverse XY-model and find a non-zero $C_4$ measure which is of the same order of magnitude than the genuine negativity. Furthermore, we observe a feature in the $C_4$ values that resembles a destructive interference with the underlying concurrence.

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Andreas Osterloh, Ralf Schützhold. 2015-12-18. The fourtangle in the transverse XY model. https://doi.org/10.1103/physreva.96.012331

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