Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Observation of Protected Photonic Edge States Induced By Real-Space
  Topological Lattice Defects   Topological defects (TDs) in crystal lattices are elementary lattice
imperfections that cannot be removed by local perturbations, due to their real
space topology. We show that adding TDs into a valley photonic crystal
generates a lattice disclination that acts like a domain wall and hosts
topological edge states. The disclination functions as a freeform waveguide
connecting a pair of TDs of opposite topological charge. This interplay between
the real-space topology of lattice defects and band topology provides a novel
scheme to implement large-scale photonic structures with complex arrangements
of robust topological waveguides and resonators.

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The categories of this paper are: astro-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: q-fin
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The categories of this paper are: math
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The categories of this paper are: stat
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The categories of this paper are: hep-lat
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The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
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The categories of this paper are: q-bio
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The categories of this paper are: hep-th
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The categories of this paper are: chem-ph
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The categories of this paper are: hep-ph
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The categories of this paper are: cs
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The categories of this paper are: cmp-lg
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The categories of this paper are: acc-phys
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The categories of this paper are: funct-an