Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Multipole expansion of strongly focussed laser beams
13
The categories of this paper are: quant-ph
7
The categories of this paper are: hep-th
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
6
The categories of this paper are: astro-ph
37
The categories of this paper are: supr-con
28
The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc
11
The categories of this paper are: hep-lat
27
The categories of this paper are: comp-gas
25
The categories of this paper are: patt-sol
22
The categories of this paper are: chao-dyn
9
The categories of this paper are: nlin
20
The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio
8
The categories of this paper are: hep-ex