Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dirac fields in the background of a magnetic flux string and spectral
  boundary conditions   We study the problem of a Dirac field in the background of an Aharonov-Bohm
flux string. We exclude the origin by imposing spectral boundary conditions at
a finite radius then shrinked to zero. Thus, we obtain a behaviour of
eigenfunctions which is compatible with the self-adjointness of the radial
Hamiltonian and the invariance under integer translations of the reduced flux.
After confining the theory to a finite region, we check the consistency with
the index theorem, and evaluate its vacuum fermionic number and Casimir energy.

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The categories of this paper are: cmp-lg
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The categories of this paper are: chem-ph
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The categories of this paper are: mtrl-th
25
The categories of this paper are: patt-sol
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The categories of this paper are: comp-gas
19
The categories of this paper are: eess
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The categories of this paper are: supr-con
15
The categories of this paper are: nucl-ex
10
The categories of this paper are: q-bio
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The categories of this paper are: dg-ga
12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex
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The categories of this paper are: stat
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The categories of this paper are: funct-an
3
The categories of this paper are: physics
33
The categories of this paper are: plasm-ph