Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Longitudinal Magnetic Dynamics and Dimensional Crossover in the
  Quasi-One-Dimensional, Spin-1/2, Heisenberg Antiferromagnet KCuF3   The spin dynamics of coupled spin-1/2, antiferromagnetic Heisenberg chains is
predicted to exhibit a novel longitudinal mode at low energies and temperatures
below the Neel temperature. This mode is a dimensional crossover effect and
reveals the presence of a limited amount of long-range antiferromagnetic order
co-existing with quantum fluctuations. In this paper the existence of such a
mode is confirmed in the model material KCuF3 using polarized and unpolarized
inelastic neutron scattering and the longitudinal polarization of the mode is
definitively established. The lineshape is broadened suggesting a reduced
lifetime due to decay into spin-waves. In addition the data shows evidence of
continuum scattering with a lower edge greater than the longitudinal mode
energy. A detailed comparison is made with theoretical predictions and
experimental work on other model materials.

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The categories of this paper are: chao-dyn
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The categories of this paper are: eess
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The categories of this paper are: bayes-an
33
The categories of this paper are: plasm-ph
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The categories of this paper are: atom-ph
3
The categories of this paper are: physics
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The categories of this paper are: acc-phys
1
The categories of this paper are: cs
6
The categories of this paper are: astro-ph
5
The categories of this paper are: gr-qc
31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
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The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
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The categories of this paper are: q-fin
10
The categories of this paper are: q-bio