Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Active locking and entanglement in type II optical parametric
  oscillators
34
The categories of this paper are: chem-ph
5
The categories of this paper are: gr-qc
15
The categories of this paper are: nucl-ex
1
The categories of this paper are: cs
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
18
The categories of this paper are: econ
23
The categories of this paper are: solv-int
24
The categories of this paper are: dg-ga
9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
11
The categories of this paper are: hep-lat
2
The categories of this paper are: math
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci