Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Artificial electromagnetic field with cold atoms in two-dimensional
  optical lattice
15
The categories of this paper are: nucl-ex
5
The categories of this paper are: gr-qc
22
The categories of this paper are: chao-dyn
24
The categories of this paper are: dg-ga
14
The categories of this paper are: math-ph
3
The categories of this paper are: physics
36
The categories of this paper are: cmp-lg
2
The categories of this paper are: math
25
The categories of this paper are: patt-sol
18
The categories of this paper are: econ
26
The categories of this paper are: bayes-an
29
The categories of this paper are: funct-an
6
The categories of this paper are: astro-ph
17
The categories of this paper are: q-fin
19
The categories of this paper are: eess
30
The categories of this paper are: q-alg