Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Discontinuities in the level density of small quantum dots under strong
  magnetic fields   Exact diagonalization studies of the level density in a six-electron quantum
dot under magnetic fields around 7 T (``filling factor'' around 1/2) are
reported. In any spin-polarization channel, two regimes are visible in the dot
excitation spectrum: one corresponding to interacting quasiparticles (i.e.
composite fermions) for excitation energies below 0.4 meV, and a second one for
energies above 0.4 meV, in which the level density (exponentially) increases at
the same rate as in the non-interacting composite-fermion model.

25
The categories of this paper are: patt-sol
17
The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph
16
The categories of this paper are: stat
32
The categories of this paper are: atom-ph
6
The categories of this paper are: astro-ph
28
The categories of this paper are: alg-geom
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
9
The categories of this paper are: nlin
21
The categories of this paper are: adap-org
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
8
The categories of this paper are: hep-ex
29
The categories of this paper are: funct-an