Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Frustrated ferromagnetic spin-1/2 chain in the magnetic field   We study the ground state properties of the Heisenberg spin-1/2 chain with
ferromagnetic nearest-neighbor and antiferromagnetic next-nearest-neighbor
interactions using two approximate methods. One of them is the Jordan-Wigner
mean-field theory and another approach based on the transformation of spin
operators to bose-ones and on the variational treatment of bosonic Hamiltonian.
Both approaches give close results for the ground state energy and the T=0
magnetization curve. It is shown that quantum fluctuations change the classical
critical exponents in the vicinity of the transition point from the
ferromagnetic to the singlet ground state. The magnetization process displays
the different behavior in the regions near and far from the transition point.
The relation of the obtained results to experimental magnetization curve in
$Rb_{2}Cu_{2}Mo_{3}O_{12}$ is discussed.

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The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex
23
The categories of this paper are: solv-int
19
The categories of this paper are: eess
34
The categories of this paper are: chem-ph
21
The categories of this paper are: adap-org
16
The categories of this paper are: stat
8
The categories of this paper are: hep-ex
3
The categories of this paper are: physics
24
The categories of this paper are: dg-ga
28
The categories of this paper are: alg-geom
22
The categories of this paper are: chao-dyn
2
The categories of this paper are: math
33
The categories of this paper are: plasm-ph