Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Measurement of excited-state transitions in cold calcium atoms by direct
  femtosecond frequency-comb spectroscopy
30
The categories of this paper are: q-alg
23
The categories of this paper are: solv-int
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con
7
The categories of this paper are: hep-th
34
The categories of this paper are: chem-ph
13
The categories of this paper are: quant-ph
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
24
The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
5
The categories of this paper are: gr-qc
11
The categories of this paper are: hep-lat
1
The categories of this paper are: cs
12
The categories of this paper are: nucl-th