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Phys. Rev. A 71, 052326 (2005) [7 pages]

Separability for lattice systems at high temperature

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Heide Narnhofer*
Institute for Theoretical Physics, University of Vienna, Austria

Received 2 November 2004; published 25 May 2005

Equilibrium states of infinite extended lattice systems at high temperature are studied with respect to their entanglement. Two notions of separability are offered. They coincide for finite systems but differ for infinitely extended ones. It is shown that for lattice systems with localized interaction for high enough temperature there exists no entanglement localized in a finite region of given size. Even more quasifree states at high temperature are also not distillably entangled for all local regions of arbitrary size. For continuous systems entanglement survives at all temperatures. In mean-field theories it is possible that local regions are not entangled but we have still entanglement hidden in the non local fluctuation algebra.

© 2005 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevA.71.052326
DOI:
10.1103/PhysRevA.71.052326
PACS:
03.67.Mn, 03.65.Ud, 05.30.Fk, 05.50.+q

*Electronic address: narnh@ap.univie.ac.at