Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The quantum anharmonic oscillator in the Heisenberg picture and multiple
  scale techniques   Multiple scale techniques are well-known in classical mechanics to give
perturbation series free from resonant terms. When applied to the quantum
anharmonic oscillator, these techniques lead to interesting features concerning
the solution of the Heisenberg equations of motion and the Hamiltonian
spectrum.

25
The categories of this paper are: patt-sol
27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th
23
The categories of this paper are: solv-int
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
28
The categories of this paper are: alg-geom
34
The categories of this paper are: chem-ph
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
24
The categories of this paper are: dg-ga
8
The categories of this paper are: hep-ex
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
18
The categories of this paper are: econ
10
The categories of this paper are: q-bio