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Titolo:
Bounding and approximating parabolas for the spectrum of Heisenberg spin systems
Autore:
Schmidt, HJ; Schnack, J; Luban, M;
Indirizzi:
Univ Osnabruck, Fachbereich Phys, D-49069 Osnabruck, Germany Univ Osnabruck Osnabruck Germany D-49069 hys, D-49069 Osnabruck, Germany Iowa State Univ, Ames Lab, Ames, IA 50011 USA Iowa State Univ Ames IA USA50011 tate Univ, Ames Lab, Ames, IA 50011 USA Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA Iowa State Univ Ames IA USA 50011 Dept Phys & Astron, Ames, IA 50011 USA
Titolo Testata:
EUROPHYSICS LETTERS
fascicolo: 1, volume: 55, anno: 2001,
pagine: 105 - 111
SICI:
0295-5075(200107)55:1<105:BAAPFT>2.0.ZU;2-9
Fonte:
ISI
Lingua:
ENG
Soggetto:
ENTRAPPING ALKALINE IONS; MAGNETIC-ANISOTROPY; CLUSTERS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
21
Recensione:
Indirizzi per estratti:
Indirizzo: Schmidt, HJ Univ Osnabruck, Fachbereich Phys, D-49069 Osnabruck, Germany Univ Osnabruck Osnabruck Germany D-49069 Osnabruck, Germany
Citazione:
H.J. Schmidt et al., "Bounding and approximating parabolas for the spectrum of Heisenberg spin systems", EUROPH LETT, 55(1), 2001, pp. 105-111

Abstract

We prove that for a wide class of quantum spin systems with isotropic Heisenberg coupling the energy eigenvalues which belong to a total spin quantumnumber S have upper and lower bounds depending at most quadratically on S. The only assumption adopted is that the mean coupling strength of any spinwith respect to its neighbours is constant for all N spins. The coefficients of the bounding parabolas are given in terms of special eigenvalues of the N x N coupling matrix which are usually easily evaluated. In addition, we show that the bounding parabolas, if properly shifted, provide very good approximations of the true boundaries of the spectrum. We present numericalexamples of frustrated rings, a cube, and an icosahedron.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 21/09/20 alle ore 09:11:50