Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Photo-current and photo-voltage oscillations in the two-dimensional
  electron system: screening and "anti-screening" of a potential profile
23
The categories of this paper are: solv-int
36
The categories of this paper are: cmp-lg
14
The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
34
The categories of this paper are: chem-ph
13
The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
19
The categories of this paper are: eess
24
The categories of this paper are: dg-ga
22
The categories of this paper are: chao-dyn
20
The categories of this paper are: acc-phys
12
The categories of this paper are: nucl-th
3
The categories of this paper are: physics
7
The categories of this paper are: hep-th
1
The categories of this paper are: cs