Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Transmission through a potential barrier in Luttinger liquids with a
  topological spin gap
8
The categories of this paper are: hep-ex
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin
32
The categories of this paper are: atom-ph
10
The categories of this paper are: q-bio
36
The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph
13
The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol
1
The categories of this paper are: cs
15
The categories of this paper are: nucl-ex
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin