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Zeitschrift für Physik B Condensed Matter
ISSN: 0722-3277 (printed version)
ISSN: 1431-584X (electronic version)
Abstract Volume 103 Issue 2 (1997) pp 231-233
Haldane gap in the S = 1 Haldane-Shastry model
P.D. Sacramento (1)(2), V.R. Vieira (2)
(1) Departamento de Física, Instituto Superior Técnico, Av. Rovisco Pais, P-1096 Lisboa Codex, Portugal
(2) Centro de Física das Interacções Fundamentais, Instituto Superior Técnico, Av. Rovisco Pais, P-1096 Lisboa Codex, Portugal
Abstract. We present evidence that the S = 1 Haldane-Shastry model has a gap in the energy spectrum, extending to the case of a model with long-range interactions results previously obtained by Haldane and, numerically, by other authors for the case of short-range interactions. We studied the groundstate and first excited state using a modified Lanczos algorithm and obtained the low temperature behavior diagonalizing exactly small chains. The correlation functions decay exponentially with distance and the low-T susceptibility decays exponentially to zero. The gap is larger than for the Heisenberg model and the correlation functions decay faster indicating a smaller correlation length.
PACS: 67.40 Db; 75.10.-b; 75.10 Jm
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Last change: May 27, 1997
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