Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Squared-field amplitude modulus and radiation intensity nonequivalence
  within nonlinear slabs   This paper presents a novel approach to wave propagation inside the
Fabry-Perot framework. It states that the time-averaged Poynting vector modulus
could be nonequivalent with the squared-field amplitude modulus. This fact
permits the introduction of a new kind of nonlinear medium whose nonlinearity
is proportional to the time-averaged Poynting vector modulus. Its transmittance
is calculated and found to differ with that obtained for the Kerr medium, whose
nonlinearity is proportional to the squared-field amplitude modulus. The latter
emphasizes the nonequivalence of these magnitudes. A space-time symmetry
analysis shows that the Poynting nonlinearity should be only possible in
noncentrosymmetric materials.

8
The categories of this paper are: hep-ex
5
The categories of this paper are: gr-qc
25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
36
The categories of this paper are: cmp-lg
6
The categories of this paper are: astro-ph
7
The categories of this paper are: hep-th
23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio
4
The categories of this paper are: cond-mat
1
The categories of this paper are: cs
24
The categories of this paper are: dg-ga
33
The categories of this paper are: plasm-ph
27
The categories of this paper are: comp-gas
15
The categories of this paper are: nucl-ex
22
The categories of this paper are: chao-dyn