Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The energy spectrum of complex periodic potentials of the Kronig-Penney
  type   We consider a complex periodic PT-symmetric potential of the Kronig-Penney
type, in order to elucidate the peculiar properties found by Bender et al. for
potentials of the form $V=i(\sin x)^{2N+1}$, and in particular the absence of
anti-periodic solutions. In this model we show explicitly why these solutions
disappear as soon as $V^*(x)\neq V(x)$, and spell out the consequences for the
form of the dispersion relation.

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The categories of this paper are: bayes-an
11
The categories of this paper are: hep-lat
0
The categories of this paper are: hep-ph
6
The categories of this paper are: astro-ph
8
The categories of this paper are: hep-ex
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The categories of this paper are: plasm-ph
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The categories of this paper are: adap-org
12
The categories of this paper are: nucl-th
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The categories of this paper are: gr-qc
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The categories of this paper are: acc-phys
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The categories of this paper are: math-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: q-fin
1
The categories of this paper are: cs
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The categories of this paper are: dg-ga