Subsystem purity as an enforcer of entanglement

We show that entanglement can always arise in the interaction of an arbitrarily large system in any mixed state with a single qubit in a pure state. This small initial purity is enough to enforce entanglement even when the total entropy is close to maximum. We demonstrate this feature using the Jayn...

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Bibliographic Details
Published inPhysical review letters Vol. 87; no. 5; p. 050401
Main Authors Bose, S, Fuentes-Guridi, I, Knight, P L, Vedral, V
Format Journal Article
LanguageEnglish
Published United States 30.07.2001
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Summary:We show that entanglement can always arise in the interaction of an arbitrarily large system in any mixed state with a single qubit in a pure state. This small initial purity is enough to enforce entanglement even when the total entropy is close to maximum. We demonstrate this feature using the Jaynes-Cummings interaction of a two-level atom in a pure state with a field in a thermal state at an arbitrarily high temperature. We find the time and temperature variation of a lower bound on the amount of entanglement produced and study the classical correlations quantified by the mutual information.
ISSN:0031-9007
DOI:10.1103/PhysRevLett.87.050401