Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Construction of the phase operator using logarithm of the annihilation
  operator
31
The categories of this paper are: ao-sci
23
The categories of this paper are: solv-int
29
The categories of this paper are: funct-an
25
The categories of this paper are: patt-sol
19
The categories of this paper are: eess
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
3
The categories of this paper are: physics
28
The categories of this paper are: alg-geom
20
The categories of this paper are: acc-phys
1
The categories of this paper are: cs
22
The categories of this paper are: chao-dyn
5
The categories of this paper are: gr-qc