Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The point spectrum of the Dirac Hamiltonian on the zero-gravity
  Kerr-Newman spacetime   In this short paper, we review the Dirac equation on the zero-gravity
Kerr-Newman spacetime. Our main objective is to provide a correspondence
between the classification of the bound states for the zGKN spectrum and the
usual hydrogenic states $1s_{1/2}$, $2s_{1/2}$, etc. of the Hydrogen atom.

29
The categories of this paper are: funct-an
30
The categories of this paper are: q-alg
27
The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat
28
The categories of this paper are: alg-geom
21
The categories of this paper are: adap-org
22
The categories of this paper are: chao-dyn
24
The categories of this paper are: dg-ga
6
The categories of this paper are: astro-ph
3
The categories of this paper are: physics
10
The categories of this paper are: q-bio
26
The categories of this paper are: bayes-an
33
The categories of this paper are: plasm-ph
12
The categories of this paper are: nucl-th
1
The categories of this paper are: cs
20
The categories of this paper are: acc-phys