Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Purcell effect in PT-symmetric waveguides   This chapter overviews the principles of the spontaneous emission rate
increase, that is the Purcell effect, in relation to the photonic parity-time
(PT) symmetry. Being focused on the system of coupled PT-symmetric optical
waveguides, we consider behaviors of the Purcell factor in PT-symmetric and
broken-PT-symmetric regimes. Surprisingly, exceptional points in a coupled
waveguide do not influence on the Purcell factor.

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The categories of this paper are: nucl-th
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The categories of this paper are: atom-ph
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The categories of this paper are: econ
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The categories of this paper are: q-alg
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The categories of this paper are: cs
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The categories of this paper are: funct-an
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The categories of this paper are: eess
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The categories of this paper are: chao-dyn
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The categories of this paper are: ao-sci
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The categories of this paper are: comp-gas
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The categories of this paper are: supr-con
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The categories of this paper are: mtrl-th
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The categories of this paper are: nlin
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The categories of this paper are: adap-org
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The categories of this paper are: hep-lat
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The categories of this paper are: dg-ga