Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Terahertz Metamaterials with Semiconductor Split-Ring Resonators for
  Magnetostatic Tunability   We studied a metasurface constituted as a periodic array of semiconductor
split-ring resonators. The resonance frequencies of the metasurface excited by
normally incident light were found to be continuously tunable in the terahertz
regime through an external magnetostatic field of suitable orientation. As such
metasurfaces can be assembled into 3D metamaterials, the foregoing conclusion
also applies to metamaterials comprising semiconductor split-ring resonators.

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The categories of this paper are: math
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The categories of this paper are: funct-an
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The categories of this paper are: nucl-ex
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The categories of this paper are: patt-sol
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The categories of this paper are: gr-qc
37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: chem-ph
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The categories of this paper are: q-bio
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The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
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The categories of this paper are: eess
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The categories of this paper are: q-alg
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The categories of this paper are: solv-int