Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Crossover from self-defocusing to discrete trapping in nonlinear
  waveguide arrays   We predict a sharp crossover from nonlinear self-defocusing to discrete
self-trapping of a narrow Gaussian beam with the increase of the refractive
index contrast in a periodic photonic lattice. We demonstrate experimentally
nonlinear discrete localization of light with defocusing nonlinearity by single
site excitation in LiNbO$_3$ waveguide arrays.

24
The categories of this paper are: dg-ga
6
The categories of this paper are: astro-ph
33
The categories of this paper are: plasm-ph
21
The categories of this paper are: adap-org
29
The categories of this paper are: funct-an
16
The categories of this paper are: stat
36
The categories of this paper are: cmp-lg
35
The categories of this paper are: mtrl-th
22
The categories of this paper are: chao-dyn
10
The categories of this paper are: q-bio
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The categories of this paper are: comp-gas
20
The categories of this paper are: acc-phys
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
0
The categories of this paper are: hep-ph
4
The categories of this paper are: cond-mat