Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The imprint of the analogue Hawking effect in subcritical flows   We study the propagation of low frequency shallow water waves on a one
dimensional flow of varying depth. When taking into account dispersive effects,
the linear propagation of long wavelength modes on uneven bottoms excites new
solutions of the dispersion relation which possess a much shorter wavelength.
The peculiarity is that one of these new solutions has a negative energy. When
the flow becomes supercritical, this mode has been shown to be responsible for
the (classical) analog of the Hawking effect. For subcritical flows, the
production of this mode has been observed numerically and experimentally, but
the precise physics governing the scattering remained unclear. In this work, we
provide an analytic treatment of this effect in subcritical flows. We analyze
the scattering of low frequency waves using a new perturbative series, derived
from a generalization of the Bremmer series. We show that the production of
short wavelength modes is governed by a complex value of the position: a
complex turning point. Using this method, we investigate various flow profiles,
and derive the main characteristics of the induced spectrum.

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The categories of this paper are: cmp-lg
18
The categories of this paper are: econ
0
The categories of this paper are: hep-ph
13
The categories of this paper are: quant-ph
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The categories of this paper are: solv-int
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The categories of this paper are: patt-sol
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The categories of this paper are: nlin
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The categories of this paper are: alg-geom
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The categories of this paper are: bayes-an
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The categories of this paper are: eess
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The categories of this paper are: nucl-ex
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The categories of this paper are: mtrl-th
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The categories of this paper are: atom-ph
2
The categories of this paper are: math
12
The categories of this paper are: nucl-th
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The categories of this paper are: chem-ph