Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spin-Wave Modes and Their Intense Excitation Effects in Skyrmion
  Crystals   We theoretically study spin-wave modes and their intense excitations
activated by microwave magnetic fields in the skyrmion-crystal phase of
insulating magnets by numerically analyzing a two-dimensional spin model using
the Landau-Lifshitz-Gilbert equation. Two peaks of spin-wave resonances with
frequencies of ~1 GHz are found for in-plane a.c. magnetic field where
distribution of the out-of-plane spin components circulates around each
skyrmion core. Directions of the circulations are opposite between these two
modes, and hence the spectra exhibit salient dependence on the circular
polarization of irradiating microwave. A breathing-type mode is also found for
out-of-plane a.c. magnetic field. By intensively exciting these collective
modes, melting of the skyrmion crystal accompanied by a red shift of the
resonant frequency is achieved within nano seconds.

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The categories of this paper are: chem-ph
0
The categories of this paper are: hep-ph
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The categories of this paper are: math-ph
17
The categories of this paper are: q-fin
33
The categories of this paper are: plasm-ph
28
The categories of this paper are: alg-geom
25
The categories of this paper are: patt-sol
18
The categories of this paper are: econ
12
The categories of this paper are: nucl-th
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The categories of this paper are: solv-int
16
The categories of this paper are: stat
32
The categories of this paper are: atom-ph
1
The categories of this paper are: cs
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
6
The categories of this paper are: astro-ph