Thermal and Magnetic Quantum Discord in Heisenberg models

We investigate how the quantum correlations (quantum discord) of a two-qubit one dimensional XYZ Heisenberg chain in thermal equilibrium depends on the temperature (T) of the bath and also on an external magnetic field B. We show that the behavior of the thermal quantum discord (QD) differs in many...

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Bibliographic Details
Published inarXiv.org
Main Authors Werlang, T, Rigolin, Gustavo
Format Paper Journal Article
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 01.04.2010
Subjects
Heisenberg theory
Phase transitions
Physics - Quantum Physics
Quantum entanglement
Quantum theory
Qubits (quantum computing)
Statistical models
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Summary:We investigate how the quantum correlations (quantum discord) of a two-qubit one dimensional XYZ Heisenberg chain in thermal equilibrium depends on the temperature (T) of the bath and also on an external magnetic field B. We show that the behavior of the thermal quantum discord (QD) differs in many unexpected ways from the thermal entanglement. For example, we show situations where QD increases with T when entanglement decreases, cases where QD increases with T even in regions with zero entanglement, and that QD signals a quantum phase transition even at finite T. We also show that by properly tuning B or the interaction between the qubits we get non-zero QD for any T and we present a new effect not seen for entanglement, the regrowth of thermal QD.
ISSN:2331-8422
DOI:10.48550/arxiv.0911.3903