Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A microscopic approach to the dimerization in the frustrated spin-1/2
  antiferromagnetic chains   The spontaneous dimerization of the frustrated spin-$1\over2$
antiferromagnetic chains is studied by a microscopic approach based on a proper
set of composite operators (i.e., pseudo-spin operators). Two approximation
schemes are developed. Firstly, a spin-wave approximation is made by a
Dyson-Mal\'eev-like boson transformation. The ground-state properties and the
triplet excitation spectra are obtained as functions of the coupling parameter.
Secondly, based on the pseudo-spin operators, a microscopic treatment is
formulated within the framework of the powerful, systematic coupled-cluster
method (CCM). Comparison between various approximations is made. The advantage
of the CCM for the purposes of systematic improvement is emphasized.

14
The categories of this paper are: math-ph
15
The categories of this paper are: nucl-ex
31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
9
The categories of this paper are: nlin
0
The categories of this paper are: hep-ph
1
The categories of this paper are: cs
37
The categories of this paper are: supr-con
17
The categories of this paper are: q-fin
22
The categories of this paper are: chao-dyn
3
The categories of this paper are: physics
6
The categories of this paper are: astro-ph
23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
27
The categories of this paper are: comp-gas