The isotropic XY model on the inhomogeneous periodic chain

The isotropic XY model on the inhomogeneous periodic chain

Author Lima, J. P. de Google Scholar
Alves, TFA Google Scholar
Goncalves, L. L. Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Univ Fed Ceara
Abstract The static and dynamic properties of the isotropic XY-model (s = 1/2) on the inhomogeneous periodic chain, composed of N segments with n different exchange interactions and magnetic moments, in a transverse field h, are obtained exactly at arbitrary temperatures. the properties are determined by introducing the generalized Jordan - Wigner transformation and by reducing the problem to a diagonalization of a finite matrix of nth order. the diagonalization procedure is discussed in detail and the critical behaviour induced by the transverse field, at T = 0, is presented. the quantum transitions are determined by analyzing the behaviour of the induced magnetization, defined as (1/n) Sigma(m=1)(n) mu(m) [S-j,m(z)] where mu(m) is the magnetic moment at site in within the segment j, as a function of the field, and the critical fields determined exactly. the dynamic correlations, [S-j,m(z)(t)S-j,m(z) (0)], and the dynamic susceptibility chi(q)(zz)(omega) are also obtained at arbitrary temperatures. Explicit results are presented in the limit T = 0, where the critical behaviour occurs, for the static susceptibility chi(q)(zz)(0) as a function of the transverse field h, and for the frequency dependency of dynamic,q susceptibility chi(q)(zz)(omega). Also in this limit, the transverse time-correlation (S-j,m(x)(t)S-j,m'(x)(0)) and the dynamic and isothermal susceptibilities, chi(q)(xx)(omega) and chi(T)(xx), are obtained for the transverse field greater or equal than the saturation field. (C) 2005 Elsevier B.V. All rights reserved.
Keywords XY model
quantum transition
inhomogeneous chain
Language English
Date 2006-03-01
Published in Journal of Magnetism and Magnetic Materials. Amsterdam: Elsevier B.V., v. 298, n. 2, p. 95-121, 2006.
ISSN 0304-8853 (Sherpa/Romeo, impact factor)
Publisher Elsevier B.V.
Extent 95-121
Origin http://dx.doi.org/10.1016/j.jmmm.2005.03.001
Access rights Closed access
Type Article
Web of Science ID WOS:000233704100004
URI http://repositorio.unifesp.br/handle/11600/28772

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