Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Scattering by a three-dimensional object composed of the simplest
  Lorentz-nonreciprocal medium   The simplest Lorentz-nonreciprocal medium has the constitutive relations
(${\bf D} =\epso {\bf E} -{\bf \Gamma}\times {\bf H}$ and ${\bf B} =\muo {\bf
H} + {\bf \Gamma}\times{\bf E}$). Scattering by a three-dimensional object
composed of this medium was investigated using the extended boundary condition
method. Scattering by this object in free space must be attributed to non-zero
$\Gamma=\vert\bf \Gamma\vert$. The differential scattering efficiency is immune
to the transformation of the incident toroidal electric field phasor into a
poloidal electric field phasor, or \textit{vice versa}, and a consequence of
this source-invariance is the polarization-state invariance of the differential
scattering efficiency when the irradiating field is a plane wave. Both the
total scattering and forward-scattering efficiencies of an ellipsoid composed
of the simplest Lorentz-nonreciprocal medium are maximum when the plane wave is
incident in a direction {coparallel (but not antiparallel)} to $\bf \Gamma$,
and the backscattering efficiency is minimum when $\bf \Gamma$ is {parallel} to
the incidence direction. The total scattering and the forward-scattering
efficiencies are maximum when the incidence direction is parallel to the
largest semi-axis of the ellipsoid if the incidence direction is coparallel
(but not antiparallel) to $\bf \Gamma$. Lorentz nonreciprocity in an object is
thus intimately connected to the shape of that object in affecting the
scattered field.

19
The categories of this paper are: eess
28
The categories of this paper are: alg-geom
27
The categories of this paper are: comp-gas
26
The categories of this paper are: bayes-an
20
The categories of this paper are: acc-phys
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
31
The categories of this paper are: ao-sci
0
The categories of this paper are: hep-ph
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
32
The categories of this paper are: atom-ph
4
The categories of this paper are: cond-mat
6
The categories of this paper are: astro-ph
34
The categories of this paper are: chem-ph