Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Reversed electromagnetic Vavilov-\v{C}erenkov radiation in naturally
  existing magnetoelectric media   We consider two semi-infinite magnetoelecteric media separated by a planar
interface whose electromagnetic response is described by axion-electrodynamics.
The time dependent Green's function characterizing this geometry is obtained by
a method which can be directly generalized to cylindrical and spherical
configurations of two magnetoelectrics separated by an interface. We establish
the far-field approximation of the Green's function and apply these results to
the case of a charged particle moving from one medium to the other at a high
constant velocity perpendicular to the interface. From the resulting angular
distribution of the radiated energy per unit frequency we provide theoretical
evidence for the emergence of reversed Vavilov-\v{C}erenkov radiation in
naturally existing magnetoelectric media. In the case where one of the
magnetolectrics is a 3D topological insulator, ${\rm TlBiSe}_2$ for example,
located in front of a regular insulator, we estimate that an average forward
Vavilov-\v{C}erenkov radiation with frequency $\sim 2.5 \,\, {\rm eV}$ ($\sim
500\,\, {\rm nm}$) will produce a highly suppressed reversed
Vavilov-\v{C}erenkov radiation which can be characterized by an effective
frequency in the range of $\sim (4\times 10^{-3}-0.5) \,\, {\rm meV}$. However,
this value compares favorably with recent measurements in left-handed
metamaterials yielding reversed Vavilov-\v{C}erenkov radiation with frequencies
of the order of $(1.2-3.9)\times 10^{-2}\,\, {\rm meV}$.

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The categories of this paper are: atom-ph
5
The categories of this paper are: gr-qc
18
The categories of this paper are: econ
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The categories of this paper are: bayes-an
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The categories of this paper are: supr-con
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The categories of this paper are: plasm-ph
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The categories of this paper are: dg-ga
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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: eess
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The categories of this paper are: physics
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The categories of this paper are: ao-sci
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-ph
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The categories of this paper are: funct-an
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The categories of this paper are: nlin