Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Escape from black holes in materials: Type II Weyl semimetals and
  generic edge states   Type II Weyl semimetals are dictated by bulk excitations with tilted light
cones, resembling the inside of black holes. We obtain generic boundary
conditions for surface boundaries of the type II Weyl semimetals near Weyl
nodes, and show that for a certain boundary condition edge states can escape
out of the "black hole" event horizon. This means that for realization of the
material "black hole" by the Type II Weyl semimetals a careful choice of the
boundary condition is necessary.

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The categories of this paper are: q-alg
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The categories of this paper are: physics
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The categories of this paper are: nucl-ex
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The categories of this paper are: math-ph
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The categories of this paper are: eess
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The categories of this paper are: bayes-an
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The categories of this paper are: econ
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The categories of this paper are: q-bio
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The categories of this paper are: nucl-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-lat
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The categories of this paper are: solv-int
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The categories of this paper are: astro-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: plasm-ph