Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Two-Photon Photocurrent in InGaN/GaN Nanowire Intermediate Band Solar
  Cells
28
The categories of this paper are: alg-geom
12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat
22
The categories of this paper are: chao-dyn
23
The categories of this paper are: solv-int
5
The categories of this paper are: gr-qc
7
The categories of this paper are: hep-th
34
The categories of this paper are: chem-ph
14
The categories of this paper are: math-ph
35
The categories of this paper are: mtrl-th
0
The categories of this paper are: hep-ph
13
The categories of this paper are: quant-ph
20
The categories of this paper are: acc-phys
18
The categories of this paper are: econ
2
The categories of this paper are: math
8
The categories of this paper are: hep-ex