Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quasi-normal frequencies: Semi-analytic results for highly damped modes   Black hole highly-damped quasi-normal frequencies (QNFs) are very often of
the form (offset)} + i n (gap). We have investigated the genericity of this
phenomenon for the Schwarzschild--deSitter (SdS) black hole by considering a
model potential that is piecewise Eckart (piecewise Poeschl-Teller), and
developing an analytic ``quantization condition'' for the highly-damped
quasi-normal frequencies. We find that the (offset) + i n(gap) behaviour is
common but not universal, with the controlling feature being whether or not the
ratio of the surface gravities is a rational number. We furthermore observed
that the relation between rational ratios of surface gravities and periodicity
of QNFs is very generic, and also occurs within different analytic approaches
applied to various types of black hole spacetimes. These observations are of
direct relevance to any physical situation where highly-damped quasi-normal
modes are important.

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The categories of this paper are: physics
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The categories of this paper are: alg-geom
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The categories of this paper are: astro-ph
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The categories of this paper are: cs
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The categories of this paper are: nucl-ex
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The categories of this paper are: math
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The categories of this paper are: funct-an
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The categories of this paper are: nlin
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The categories of this paper are: chem-ph
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The categories of this paper are: dg-ga
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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: quant-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-lat
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The categories of this paper are: math-ph