Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Observation of Photonic Topological Valley-Hall Edge States   We experimentally demonstrate topological edge states arising from the
valley-Hall effect in twodimensional honeycomb photonic lattices with broken
inversion symmetry. We break inversion symmetry by detuning the refractive
indices of the two honeycomb sublattices, giving rise to a boron nitride-like
band structure. The edge states therefore exist along the domain walls between
regions of opposite valley Chern numbers. We probe both the armchair and
zig-zag domain walls and show that the former become gapped for any detuning,
whereas the latter remain ungapped until a cutoff is reached. The valley-Hall
effect provides a new mechanism for the realization of time-reversal invariant
photonic topological insulators.

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The categories of this paper are: alg-geom
10
The categories of this paper are: q-bio
0
The categories of this paper are: hep-ph
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The categories of this paper are: comp-gas
1
The categories of this paper are: cs
21
The categories of this paper are: adap-org
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The categories of this paper are: quant-ph
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The categories of this paper are: chem-ph
2
The categories of this paper are: math
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The categories of this paper are: cmp-lg
7
The categories of this paper are: hep-th
20
The categories of this paper are: acc-phys
9
The categories of this paper are: nlin
25
The categories of this paper are: patt-sol
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The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat