Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Nonlinear terahertz metamaterials via field-enhanced carrier dynamics in
  GaAs
13
The categories of this paper are: quant-ph
37
The categories of this paper are: supr-con
22
The categories of this paper are: chao-dyn
12
The categories of this paper are: nucl-th
10
The categories of this paper are: q-bio
2
The categories of this paper are: math
1
The categories of this paper are: cs
25
The categories of this paper are: patt-sol
23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex
19
The categories of this paper are: eess
7
The categories of this paper are: hep-th
6
The categories of this paper are: astro-ph
21
The categories of this paper are: adap-org
17
The categories of this paper are: q-fin
31
The categories of this paper are: ao-sci