Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A particle mechanism for the index of refraction   We propose to go away from the electromagnetic wave description of light and
to explain through a purely corpuscular and neutral approach, the phenomenon of
the slowing down of light in a transparent medium. The quantum predictions and
ours are compared against experimental refractive indices. In our framework the
optical Kerr phenomenon finds a very natural interpretation and its numerical
values are obtained easily

15
The categories of this paper are: nucl-ex
36
The categories of this paper are: cmp-lg
11
The categories of this paper are: hep-lat
0
The categories of this paper are: hep-ph
23
The categories of this paper are: solv-int
20
The categories of this paper are: acc-phys
19
The categories of this paper are: eess
2
The categories of this paper are: math
6
The categories of this paper are: astro-ph
12
The categories of this paper are: nucl-th
22
The categories of this paper are: chao-dyn
16
The categories of this paper are: stat
8
The categories of this paper are: hep-ex
24
The categories of this paper are: dg-ga
26
The categories of this paper are: bayes-an
14
The categories of this paper are: math-ph