Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Phase-merging Enhanced Harmonic Generation Free-electron Laser
8
The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg
37
The categories of this paper are: supr-con
17
The categories of this paper are: q-fin
13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs
5
The categories of this paper are: gr-qc
11
The categories of this paper are: hep-lat
24
The categories of this paper are: dg-ga
33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
14
The categories of this paper are: math-ph
34
The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
29
The categories of this paper are: funct-an
15
The categories of this paper are: nucl-ex