Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Optical dichroism in nanotubes   Utilizing the line-group symmetry of single-wall nanotubes, we have assigned
their electron-energy bands by the symmetry-based quantum numbers. The
selection rules for optical absorption are presented in terms of these quantum
numbers. Different interband transitions become allowed as the polarization of
incident light is varied, and we predict a substantial optical dichroism. We
propose how to observe this effect in experiments on a single nanotube, and how
it can be used to control quantum transport in nanotubes to obtain information
about the structure.

16
The categories of this paper are: stat
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
23
The categories of this paper are: solv-int
6
The categories of this paper are: astro-ph
27
The categories of this paper are: comp-gas
1
The categories of this paper are: cs
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
20
The categories of this paper are: acc-phys
0
The categories of this paper are: hep-ph
5
The categories of this paper are: gr-qc
24
The categories of this paper are: dg-ga
28
The categories of this paper are: alg-geom