Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hopf-link multi-Weyl-loop topological semimetals   We construct a generic two-band model which can describe topological Weyl
semimetals with multiple closed Weyl loops. All the existing multi-Weyl-loop
semimetals including the nodal-net, or nodal-chain and Hopf-link states can be
examined within one same framework. Based on a two-loop model, the
corresponding drum-head surface states for these topologically different bulk
states are studied and compared with each other. The connection of our model
with Hopf insulators is also discussed. Furthermore, to identify experimentally
these topologically different Weyl semimetal states, especially distinguish the
Hopf-link from unlinked ones, we also investigate their Landau levels. It is
found that the Hopf-link state can be characterized by the existence of a
quadruply degenerate zero-energy Landau band, regardless of the direction of
the magnetic field.

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The categories of this paper are: ao-sci
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The categories of this paper are: atom-ph
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The categories of this paper are: eess
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The categories of this paper are: dg-ga
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The categories of this paper are: alg-geom
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The categories of this paper are: econ
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The categories of this paper are: q-fin
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The categories of this paper are: hep-th
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The categories of this paper are: patt-sol
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The categories of this paper are: q-bio
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The categories of this paper are: chao-dyn
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The categories of this paper are: solv-int
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The categories of this paper are: hep-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: nucl-ex
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The categories of this paper are: stat