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Enhancement of pairwise entanglement from $\mathbbm{Z}_2$ symmetry breaking

A. Osterloh·G. Palacios·S. Montangero
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Abstract

We study the effect of symmetry breaking in a quantum phase transition on pairwise entanglement in spin-1/2 models. We give a set of conditions on correlation functions a model has to meet in order to keep the pairwise entanglement unchanged by a parity symmetry breaking. It turns out that all mean-field solvable models do meet this requirement, whereas the presence of strong correlations leads to a violation of this condition. This results in an order-induced enhancement of entanglement, and we report on two examples where this takes place.

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A. Osterloh, G. Palacios, S. Montangero. 2007-01-31. Enhancement of pairwise entanglement from $\mathbbm{Z}_2$ symmetry breaking. https://doi.org/10.1103/physrevlett.97.257201

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