Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gapless surface states in a lattice of coupled cavities: a photonic
  analog of topological crystalline insulators   We show that a tetragonal lattice of weakly interacting cavities with
uniaxial electromagnetic response is the photonic counterpart of topological
crystalline insulators, a new topological phase of atomic band insulators.
Namely, the frequency band structure stemming from the interaction of resonant
modes of the individual cavities exhibits an omnidirectional band gap within
which gapless surface states emerge for finite slabs of the lattice. Due to the
equivalence of a topological crystalline insulator with its photonic-crystal
analog, the frequency band structure of the latter can be characterized by a
$Z_{2}$ topological invariant. Such a topological photonic crystal can be
realized in the microwave regime as a three-dimensional lattice of dielectric
particles embedded within a continuous network of thin metallic wires.

27
The categories of this paper are: comp-gas
2
The categories of this paper are: math
20
The categories of this paper are: acc-phys
33
The categories of this paper are: plasm-ph
32
The categories of this paper are: atom-ph
24
The categories of this paper are: dg-ga
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph
21
The categories of this paper are: adap-org
19
The categories of this paper are: eess
30
The categories of this paper are: q-alg
23
The categories of this paper are: solv-int
37
The categories of this paper are: supr-con
10
The categories of this paper are: q-bio
35
The categories of this paper are: mtrl-th
0
The categories of this paper are: hep-ph