Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Classical Propagation of Light in Spatio-Temporal Periodic Media   We analyze the propagation of electromagnetic waves in media where the
dielectric constants undergo rapid temporal periodic modulation. Both spatially
homogeneous and periodic media are studied. Fast periodic temporal modulation
of the dielectric constant of a homogeneous medium leads to existence of
photonic band-gap like phenomena. In the presence of both spatial and tem-
poral periodicity the electromagnetic spectrum is described in a
four-dimensional cube, defining an effective Brillouin zone. In the case of
incommensurability between space and time periodicities, completely dispersed
point spectra exist.

31
The categories of this paper are: ao-sci
4
The categories of this paper are: cond-mat
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
2
The categories of this paper are: math
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph
32
The categories of this paper are: atom-ph
23
The categories of this paper are: solv-int
18
The categories of this paper are: econ
26
The categories of this paper are: bayes-an
8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
13
The categories of this paper are: quant-ph
9
The categories of this paper are: nlin
19
The categories of this paper are: eess