Ground-state properties of linear-exchange quantum spin models

The authors study a class of one-dimensional antiferromagnetic quantum spin-1/2 models using DMRG. The exchange interaction in these models decreases linearly with the separation between the spins, ... for ..., where R is a positive integer greater than or equal to 2. For ... R, the interaction is z...

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Bibliographic Details
Published in:Europhysics letters 2012-10, Vol.100 (2), p.1-1
Main Authors: Danu, Bimla, Kumar, Brijesh, Pai, Ramesh V
Format: Article
Language:English
Subjects:
Antiferromagnetism
Asymptotic properties
Dimers
Ground state
Integers
Mathematical analysis
Mathematical models
Symbols
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Summary:The authors study a class of one-dimensional antiferromagnetic quantum spin-1/2 models using DMRG. The exchange interaction in these models decreases linearly with the separation between the spins, ... for ..., where R is a positive integer greater than or equal to 2. For ... R, the interaction is zero. It is known that all the odd-R models have the same exact dimer ground state as the Majumdar-Ghosh (MG) model. In fact, R =3 is the MG model. However, for an even R, the exact ground state is not known in general, except for R = 2 and the asymptotic limit of R in which the MG dimer state emerges as the exact ground state. Therefore, the authors numerically study the ground-state properties of the finite even-R ... 2 models, particularly for R=4, 6 and 8. They find that, unlike R = 2, the higher even-R models are spin-gapped, and exhibit robust dimer order of the MG type in the ground state. (ProQuest: ... denotes formulae/symbols omitted.)
ISSN:0295-5075
1286-4854