Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Gauge Covariance and Spin Current Conservation in the Gauge Field
  Formulation of Systems with Spin-Orbit Coupling
30
The categories of this paper are: q-alg
19
The categories of this paper are: eess
20
The categories of this paper are: acc-phys
27
The categories of this paper are: comp-gas
5
The categories of this paper are: gr-qc
1
The categories of this paper are: cs
37
The categories of this paper are: supr-con
18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
23
The categories of this paper are: solv-int
17
The categories of this paper are: q-fin
31
The categories of this paper are: ao-sci