Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnetic excitations in the spin-1 anisotropic antiferromagnet
  $NiCl_2-4SC(NH_2)_2$   The spin-1 anisotropic antiferromagnet NiCl_2-4SC(NH2)_2 exhibits a
field-induced quantum phase transition that is formally analogous to
Bose-Einstein condensation. Here we present results of systematic high-field
electron spin resonance (ESR) experimental and theoretical studies of this
compound with a special emphasis on single-ion two-magnon bound states. In
order to clarify some remaining discrepancies between theory and experiment,
the frequency-field dependence of magnetic excitations in this material is
reanalyzed. In particular, a more comprehensive interpretation of the
experimental signature of single-ion two-magnon bound states is shown to be
fully consistent with theoretical results. We also clarify the structure of the
ESR spectrum in the so-called intermediate phase.

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The categories of this paper are: supr-con
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The categories of this paper are: math
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The categories of this paper are: alg-geom
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The categories of this paper are: mtrl-th
1
The categories of this paper are: cs
7
The categories of this paper are: hep-th
6
The categories of this paper are: astro-ph
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The categories of this paper are: funct-an
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The categories of this paper are: dg-ga
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The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
0
The categories of this paper are: hep-ph
25
The categories of this paper are: patt-sol
13
The categories of this paper are: quant-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: stat