Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Coherent Propagation of Spin Helices in a Quantum-Well Confined Electron
  Gas
27
The categories of this paper are: comp-gas
3
The categories of this paper are: physics
24
The categories of this paper are: dg-ga
5
The categories of this paper are: gr-qc
13
The categories of this paper are: quant-ph
15
The categories of this paper are: nucl-ex
1
The categories of this paper are: cs
23
The categories of this paper are: solv-int
6
The categories of this paper are: astro-ph
9
The categories of this paper are: nlin
34
The categories of this paper are: chem-ph
33
The categories of this paper are: plasm-ph
35
The categories of this paper are: mtrl-th
11
The categories of this paper are: hep-lat
29
The categories of this paper are: funct-an
31
The categories of this paper are: ao-sci