Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spin Order and Excitations in Triangular Antiferromagnet La2Ca2MnO7   We report a spin S = 3/2 triangular antiferromagnet with nearest-neighbor
coupling J = 0.29 meV in La2Ca2MnO7. A genuinely two-dimensional,
three-sublattice order develops below 2.80 K << the Weiss constant (25 K). The
spin excitations deviate substantially from linear spin-wave theory, suggesting
that magnon breakdown occurs in the material. Such a breakdown has been
anticipated in recent theoretical studies, although the excitation spectrum
remains to be accounted for.

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The categories of this paper are: comp-gas
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The categories of this paper are: math
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The categories of this paper are: solv-int
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The categories of this paper are: q-alg
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The categories of this paper are: bayes-an
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The categories of this paper are: hep-lat
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The categories of this paper are: physics
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The categories of this paper are: cmp-lg
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The categories of this paper are: econ
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The categories of this paper are: hep-ex
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The categories of this paper are: supr-con
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The categories of this paper are: quant-ph
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The categories of this paper are: gr-qc
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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: q-fin