Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Infrared generation in low-dimensional semiconductor heterostructures
  via quantum coherence
37
The categories of this paper are: supr-con
20
The categories of this paper are: acc-phys
18
The categories of this paper are: econ
3
The categories of this paper are: physics
24
The categories of this paper are: dg-ga
6
The categories of this paper are: astro-ph
14
The categories of this paper are: math-ph
16
The categories of this paper are: stat
29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
28
The categories of this paper are: alg-geom
34
The categories of this paper are: chem-ph
19
The categories of this paper are: eess
17
The categories of this paper are: q-fin
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph