Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Measurement of statistical nuclear spin polarization in a nanoscale GaAs
  sample
33
The categories of this paper are: plasm-ph
8
The categories of this paper are: hep-ex
18
The categories of this paper are: econ
17
The categories of this paper are: q-fin
21
The categories of this paper are: adap-org
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
5
The categories of this paper are: gr-qc
31
The categories of this paper are: ao-sci
3
The categories of this paper are: physics
28
The categories of this paper are: alg-geom
15
The categories of this paper are: nucl-ex
14
The categories of this paper are: math-ph
23
The categories of this paper are: solv-int
22
The categories of this paper are: chao-dyn
11
The categories of this paper are: hep-lat