Perturbation theory by flow equations: dimerized and frustrated S=1/2 chain

被引：213

作者：

Knetter, C ^{[1
]}

Uhrig, GS ^{[1
]}

机构：

[1] Univ Cologne, Inst Theoret Phys, D-50937 Cologne, Germany

来源：

EUROPEAN PHYSICAL JOURNAL B | 2000年 / 13卷 / 02期

关键词：

D O I：

10.1007/s100510050026

中图分类号：

O469 [凝聚态物理学];

学科分类号：

070205 ;

摘要：

The flow equation method (Wegner, 1994) is used as continuous unitary transformation to construct perturbatively effective Hamiltonians. The method is illustrated in detail for dimerized and frustrated antiferromagnetic S = 1/2 chains. The effective Hamiltonians conserve the number of elementary excitations which are S = 1 magnons for the dimerized chains. The sectors of different; number of excitations are clearly separated. Easy-to-use results for the gap, the dispersion and the ground state energies of the chains are provided.

引用

页码：209 / 225

页数：17

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