Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Bethe ansatz for the Harper equation: Solution for a small
  commensurability parameter   The Harper equation describes an electron on a 2D lattice in magnetic field
and a particle on a 1D lattice in a periodic potential, in general,
incommensurate with the lattice potential. We find the distribution of the
roots of Bethe ansatz equations associated with the Harper equation in the
limit as alpha=1/Q tends to 0, where alpha is the commensurability parameter (Q
is integer). Using the knowledge of this distribution we calculate the higher
and lower boundaries of the spectrum of the Harper equation for small alpha.
The result is in agreement with the semiclassical argument, which can be used
for small alpha.

26
The categories of this paper are: bayes-an
11
The categories of this paper are: hep-lat
25
The categories of this paper are: patt-sol
1
The categories of this paper are: cs
28
The categories of this paper are: alg-geom
17
The categories of this paper are: q-fin
15
The categories of this paper are: nucl-ex
37
The categories of this paper are: supr-con
27
The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio
24
The categories of this paper are: dg-ga
31
The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc
8
The categories of this paper are: hep-ex
2
The categories of this paper are: math