Pairwise entanglement in the XX model with a magnetic impurity
- 3 May 2002
- journal article
- Published by IOP Publishing in Journal of Physics A: General Physics
- Vol. 35 (19) , 4293-4300
- https://doi.org/10.1088/0305-4470/35/19/310
Abstract
For a three-qubit Heisenberg model in a uniform magnetic field, the pairwise thermal entanglement of any two sites is identical due to the exchange symmetry of sites. In this paper we consider the effect of a non-uniform magnetic field on the Heisenberg model, modelling a magnetic impurity on one site. Since pairwise entanglement is calculated by tracing out one of the three sites, the entanglement clearly depends on which site the impurity is located. When the impurity is located on the site which is traced out, that is, when it acts as an external field of the pair, the entanglement can be enhanced to the maximal value 1; while when the field acts on a site of the pair the corresponding concurrence can only be increased from 1/3 to 2/3.Keywords
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This publication has 31 references indexed in Scilit:
- Quantum entanglement in fermionic latticesPhysical Review A, 2002
- Entanglement in a two-identical-particle systemPhysical Review A, 2001
- Quantum correlations in two-fermion systemsPhysical Review A, 2001
- Entanglement of quantum evolutionsPhysical Review A, 2001
- Entangling Operations and Their Implementation Using a Small Amount of EntanglementPhysical Review Letters, 2001
- On local invariants of pure three-qubit statesJournal of Physics A: General Physics, 2001
- Three qubits can be entangled in two inequivalent waysPhysical Review A, 2000
- Entangling power of quantum evolutionsPhysical Review A, 2000
- Distributed entanglementPhysical Review A, 2000
- Quantum information and computationNature, 2000