Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: On Nondemolition Measurements of Photon Number: A Comment on
  quant-ph/0612031
31
The categories of this paper are: ao-sci
35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol
11
The categories of this paper are: hep-lat
14
The categories of this paper are: math-ph
19
The categories of this paper are: eess
1
The categories of this paper are: cs
6
The categories of this paper are: astro-ph
32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
22
The categories of this paper are: chao-dyn
4
The categories of this paper are: cond-mat
36
The categories of this paper are: cmp-lg