Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The cylindrical \delta-potential and the Dirac equation   In this article we discuss the Dirac equation in the presence of an
attractive cylindrical \delta-shell potential V(\rho)=-a\delta(\rho-\rho_0),
where \rho is the radial coordinate and a>0. We present a detailed discussion
on the boundary conditions the wave function has to satisfy when crossing the
support of the potential, proceeding then to explore the dependence of the
ground state on the parameter a, analyzing the occurrence of supercritical
effects. We also apply the Foldy-Wouthuysen transformation, discussing the
non-relativistic limit of this problem.

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The categories of this paper are: hep-ex
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The categories of this paper are: chao-dyn
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The categories of this paper are: dg-ga
32
The categories of this paper are: atom-ph
31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
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The categories of this paper are: cond-mat
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The categories of this paper are: solv-int
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The categories of this paper are: physics
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The categories of this paper are: nlin
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The categories of this paper are: comp-gas
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The categories of this paper are: cmp-lg
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The categories of this paper are: math-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: eess