Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Negative phase velocity in isotropic dielectric-magnetic mediums via
  homogenization   We report on a strategy for achieving negative phase velocity (NPV) in a
homogenized composite medium (HCM) conceptualized using the Bruggeman
formalism. The constituent material phases of the HCM do not support NPV
propagation. The HCM and its constituent phases are isotropic
dielectric-magnetic mediums; the real parts of their
permittivities/permeabilities are negative-valued whereas the real parts of
their permeabilities/permittivities are positive-valued.

10
The categories of this paper are: q-bio
9
The categories of this paper are: nlin
32
The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
36
The categories of this paper are: cmp-lg
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
30
The categories of this paper are: q-alg
28
The categories of this paper are: alg-geom
20
The categories of this paper are: acc-phys
19
The categories of this paper are: eess
17
The categories of this paper are: q-fin
13
The categories of this paper are: quant-ph
22
The categories of this paper are: chao-dyn
0
The categories of this paper are: hep-ph