Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Light Bullet Modes in Self-Induced-Transparency Media with Refractive
  Index Modulation   We predict the existence of a new type of spatiotemporal solitons ("light
bullets") in two-dimensional self-induced-transparency media with refractive
index modulation in the direction transverse to that of pulse propagation.
These self-localized guided modes are found in an approximate analytical form,
their existence and stability being confirmed by numerical simulations, and may
have advantageous properties for signal transmission.

31
The categories of this paper are: ao-sci
14
The categories of this paper are: math-ph
5
The categories of this paper are: gr-qc
32
The categories of this paper are: atom-ph
26
The categories of this paper are: bayes-an
10
The categories of this paper are: q-bio
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
11
The categories of this paper are: hep-lat
17
The categories of this paper are: q-fin
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
1
The categories of this paper are: cs
13
The categories of this paper are: quant-ph
12
The categories of this paper are: nucl-th