Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On multiphoton absorption by molecules   Rabi frequencies for multiphoton absorption by atoms or molecules that can be
characterized as two- or three-level systems are obtained in the cases of
single and double laser perturbations. If the ambiguity in the origin of
absolute energy is conveniently gauged off in the three-level model, there
appears an additional non linear frequency which is originated from the
separate evolution of a relative-frequency component induced in the whole
system by the simultaneous action of the two perturbations.

18
The categories of this paper are: econ
25
The categories of this paper are: patt-sol
23
The categories of this paper are: solv-int
26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th
32
The categories of this paper are: atom-ph
16
The categories of this paper are: stat
36
The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
17
The categories of this paper are: q-fin
4
The categories of this paper are: cond-mat
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con