Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Spin-split bands cause the indirect band gap of (CH$_3$NH$_3$)PbI$_3$:
  Experimental evidence from circular photogalvanic effect
2
The categories of this paper are: math
15
The categories of this paper are: nucl-ex
24
The categories of this paper are: dg-ga
8
The categories of this paper are: hep-ex
34
The categories of this paper are: chem-ph
7
The categories of this paper are: hep-th
31
The categories of this paper are: ao-sci
16
The categories of this paper are: stat
19
The categories of this paper are: eess
13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin
6
The categories of this paper are: astro-ph
28
The categories of this paper are: alg-geom
29
The categories of this paper are: funct-an