Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum corrections to the spin-wave spectrum of La$_2$CuO$_4$ in an
  external magnetic field   The effects of quantum fluctuations on the magnetic field dependence of the
spin-wave gaps in the lamellar antiferromagnet La$_2$CuO$_4$ are considered.
Nonlinear corrections to the spin-wave spectrum are calculated to leading order
in 1/S, where $S$ is the localized spin. The nearest-neighbor exchange
interactions between the Cu spins as well as the Dzyaloshinskii-Moriya
interactions are taken into account. Using the experimental values of the
components of the $g$-factor tensor, we get a satisfactory agreement with the
experimental results for the field dependence of the gaps by Gozar {\it et al.}
[Phys. Rev. Lett. {\bf 93}, 027001 (2004)], and obtain consistent values of the
in-plane and inter-plane coupling constants. The field dependence of the
dispersion of spin waves propagating perpendicular to the CuO$_2$ planes is
also discussed.

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The categories of this paper are: math
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The categories of this paper are: stat
19
The categories of this paper are: eess
6
The categories of this paper are: astro-ph
8
The categories of this paper are: hep-ex
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The categories of this paper are: nucl-th
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The categories of this paper are: adap-org
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The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
26
The categories of this paper are: bayes-an
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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-alg
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The categories of this paper are: acc-phys
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The categories of this paper are: physics
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The categories of this paper are: hep-ph