Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Causal signal transmission by quantum fields. I. Response of the
  harmonic oscillator   It is shown that response properties of a quantum harmonic oscillator are in
essence those of a classical oscillator, and that, paradoxical as it may be,
these classical properties underlie all quantum dynamical properties of the
system. The results are extended to non-interacting bosonic fields, both
neutral and charged.

32
The categories of this paper are: atom-ph
19
The categories of this paper are: eess
26
The categories of this paper are: bayes-an
25
The categories of this paper are: patt-sol
1
The categories of this paper are: cs
36
The categories of this paper are: cmp-lg
20
The categories of this paper are: acc-phys
0
The categories of this paper are: hep-ph
35
The categories of this paper are: mtrl-th
18
The categories of this paper are: econ
6
The categories of this paper are: astro-ph
7
The categories of this paper are: hep-th
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
16
The categories of this paper are: stat
24
The categories of this paper are: dg-ga