Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Influence of Magnetism on Phonons in CaFe2As2 Via Inelastic X-ray
  Scattering   In the iron pnictides, the strong sensitivity of the iron magnetic moment to
the arsenic position suggests a significant relationship between phonons and
magnetism. We measured the phonon dispersion of several branches in the high
temperature tetragonal phase of CaFe2As2 using inelastic x-ray scattering on
single-crystal samples. These measurements were compared to ab initio
calculations of the phonons. Spin polarized calculations imposing the
antiferromagnetic order present in the low temperature orthorhombic phase
dramatically improve agreement between theory and experiment. This is discussed
in terms of the strong antiferromagnetic correlations that are known to persist
in the tetragonal phase.

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The categories of this paper are: nucl-th
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The categories of this paper are: funct-an
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The categories of this paper are: econ
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The categories of this paper are: plasm-ph
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The categories of this paper are: stat
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The categories of this paper are: ao-sci
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The categories of this paper are: patt-sol
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The categories of this paper are: quant-ph
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The categories of this paper are: eess
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The categories of this paper are: math
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The categories of this paper are: dg-ga
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The categories of this paper are: comp-gas
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The categories of this paper are: solv-int
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The categories of this paper are: hep-ex
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The categories of this paper are: atom-ph
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The categories of this paper are: acc-phys