Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Exciton spectrum in multi-shell hexagonal semiconductor nanotube   The theory of exciton spectrum in multi-shell hexagonal semiconductor
nanotube is developed within the effective masses and rectangular potentials
approximations using the method of effective potential. It is shown that the
exciton binding energy for all states non-monotonously depends on the inner
wire diameter, approaching several minimal and maximal magnitudes. The obtained
theoretical results explain well the experimental positions of luminescence
peaks for GaAs/Al_{0.4}Ga_{0.6}As nanotubes.

26
The categories of this paper are: bayes-an
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
5
The categories of this paper are: gr-qc
11
The categories of this paper are: hep-lat
12
The categories of this paper are: nucl-th
19
The categories of this paper are: eess
10
The categories of this paper are: q-bio
6
The categories of this paper are: astro-ph
15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
16
The categories of this paper are: stat
7
The categories of this paper are: hep-th
0
The categories of this paper are: hep-ph
3
The categories of this paper are: physics
17
The categories of this paper are: q-fin