Thermal entanglement in fully connected spin systems and its random-phase-approximation description

We examine the thermal pairwise entanglement in a symmetric system of n spins fully connected through anisotropic XYZ-type couplings embedded in a transverse magnetic field. We consider both the exact evaluation together with that obtained with the static path+random phase approximation RPA and the...

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Detalles Bibliográficos
Autores: Matera, Juan Mauricio, Rossignoli, Raúl Dante, Canosa, Norma Beatriz
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2008
País:Argentina
Institución:Universidad Nacional de La Plata
Repositorio:SEDICI (UNLP)
Idioma:inglés
OAI Identifier:oai:sedici.unlp.edu.ar:10915/154215
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/154215
Access Level:acceso abierto
Palabra clave:Física
Entanglement measures
Entanglement and quantum nonlocality
Quantized spin models
Descripción
Sumario:We examine the thermal pairwise entanglement in a symmetric system of n spins fully connected through anisotropic XYZ-type couplings embedded in a transverse magnetic field. We consider both the exact evaluation together with that obtained with the static path+random phase approximation RPA and the ensuing mean field+RPA. The latter is shown to provide an accurate analytic description of both the parallel and antiparallel thermal concurrence in large systems. We also analyze the limit temperature for pairwise entanglement, which is shown to increase for large fields and to decrease logarithmically with increasing n. Special finite-size effects are also discussed.