Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnon nodal-line semimetals and drumhead surface states in anisotropic
  pyrochlore ferromagnets   We introduce a new type of topological magnon matter: the magnonic pendant to
electronic nodal-line semimetals. Magnon spectra of anisotropic pyrochlore
ferromagnets feature twofold degeneracies of magnon bands along a closed loop
in reciprocal space. These magnon nodal lines are topologically protected by
the coexistence of inversion and time-reversal symmetry; they require the
absence of spin-orbit interaction (no Dzyaloshinskii-Moriya interaction). We
calculate the topological invariants of the nodal lines and show that details
of the associated magnon drumhead surface states depend strongly on the
termination of the surface. Magnon nodal-line semimetals complete the family of
topological magnons in three-dimensional ferromagnetic materials.

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The categories of this paper are: nucl-ex
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-ph
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The categories of this paper are: q-alg
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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: cs
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The categories of this paper are: q-bio
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The categories of this paper are: eess
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The categories of this paper are: q-fin
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The categories of this paper are: funct-an
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The categories of this paper are: gr-qc
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The categories of this paper are: solv-int
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The categories of this paper are: supr-con
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The categories of this paper are: alg-geom
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The categories of this paper are: cmp-lg