Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Landau levels in a topological insulator   Two recent experiments successfully observed Landau levels in the tunneling
spectra of the topological insulator Bi2Se3. To mimic the influence of a
scanning tunneling microscope tip on the Landau levels we solve the
two-dimensional Dirac equation in the presence of a localized electrostatic
potential. We find that the STM tip not only shifts the Landau levels, but also
suppresses for a realistic choice of parameters the negative branch of Landau
levels.

5
The categories of this paper are: gr-qc
24
The categories of this paper are: dg-ga
33
The categories of this paper are: plasm-ph
29
The categories of this paper are: funct-an
7
The categories of this paper are: hep-th
13
The categories of this paper are: quant-ph
30
The categories of this paper are: q-alg
3
The categories of this paper are: physics
26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th
10
The categories of this paper are: q-bio
8
The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol
31
The categories of this paper are: ao-sci
34
The categories of this paper are: chem-ph
11
The categories of this paper are: hep-lat