Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Fractional periodic persistent current in a twisted normal metal loop:
  an exact result
22
The categories of this paper are: chao-dyn
2
The categories of this paper are: math
5
The categories of this paper are: gr-qc
30
The categories of this paper are: q-alg
17
The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph
15
The categories of this paper are: nucl-ex
14
The categories of this paper are: math-ph
31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th
37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
25
The categories of this paper are: patt-sol
19
The categories of this paper are: eess