Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spin 1/2 particle in the field of the Dirac string on the background of
  de Sitter space-time   The Dirac monopole string is specified for de Sitter cosmological model.
Dirac equation for spin 1/2 particle in presence of this monopole has been
examined on the background of de Sitter space-time in static coordinates.
Instead of spinor monopole harmonics, the technique of Wigner D-functions is
used. After separation of the variables, detailed analysis of the radial
equations is performed; four types of solutions, singular, regular, in- and
out- running waves, are constructed in terms of hypergeometric functions. The
complete set of spinor wave solutions \Psi_{\epsilon, j,m, \lambda}(t,r,
\theta, \phi) has been constructed, special attention is given to treating the
states of minimal values of the total angular moment j_{\min}.

27
The categories of this paper are: comp-gas
15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
29
The categories of this paper are: funct-an
19
The categories of this paper are: eess
37
The categories of this paper are: supr-con
21
The categories of this paper are: adap-org
36
The categories of this paper are: cmp-lg
4
The categories of this paper are: cond-mat
34
The categories of this paper are: chem-ph
7
The categories of this paper are: hep-th
11
The categories of this paper are: hep-lat
23
The categories of this paper are: solv-int
16
The categories of this paper are: stat
1
The categories of this paper are: cs