Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Second-order nonlinear optical effects of spin currents
24
The categories of this paper are: dg-ga
37
The categories of this paper are: supr-con
11
The categories of this paper are: hep-lat
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
30
The categories of this paper are: q-alg
17
The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th
3
The categories of this paper are: physics
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
36
The categories of this paper are: cmp-lg
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
34
The categories of this paper are: chem-ph
21
The categories of this paper are: adap-org