Quantum entanglement in the two-impurity Kondo model

Cho, SY and McKenzie, RH (2006) Quantum entanglement in the two-impurity Kondo model. Physical Review A, 73 1: . doi:10.1103/PhysRevA.73.012109

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Author Cho, SY
McKenzie, RH
Title Quantum entanglement in the two-impurity Kondo model
Journal name Physical Review A   Check publisher's open access policy
ISSN 1050-2947
Publication date 2006-01-01
Year available 2006
Sub-type Article (original research)
DOI 10.1103/PhysRevA.73.012109
Open Access Status File (Publisher version)
Volume 73
Issue 1
Total pages 7
Editor B. Crasemann
Place of publication United States
Publisher American Physical Society
Language eng
Subject C1
240200 Theoretical and Condensed Matter Physics
780102 Physical sciences
Abstract In order to quantify quantum entanglement in two-impurity Kondo systems, we calculate the concurrence, negativity, and von Neumann entropy. The entanglement of the two Kondo impurities is shown to be determined by two competing many-body effects, namely the Kondo effect and the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction, I. Due to the spin-rotational invariance of the ground state, the concurrence and negativity are uniquely determined by the spin-spin correlation between the impurities. It is found that there exists a critical minimum value of the antiferromagnetic correlation between the impurity spins which is necessary for entanglement of the two impurity spins. The critical value is discussed in relation with the unstable fixed point in the two-impurity Kondo problem. Specifically, at the fixed point there is no entanglement between the impurity spins. Entanglement will only be created [and quantum information processing (QIP) will only be possible] if the RKKY interaction exchange energy, I, is at least several times larger than the Kondo temperature, T-K. Quantitative criteria for QIP are given in terms of the impurity spin-spin correlation.
Keyword Optics
Physics, Atomic, Molecular & Chemical
Q-Index Code C1
Institutional Status UQ

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Created: Wed, 15 Aug 2007, 19:08:38 EST