Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum transport properties of two-dimensional electron gases under
  high magnetic fields   We study quantum transport properties of two-dimensional electron gases under
high perpendicular magnetic fields. For this purpose, we reformulate the
high-field expansion, usually done in the operatorial language of the
guiding-center coordinates, in terms of vortex states within the framework of
real-time Green functions. These vortex states arise naturally from the
consideration that the Landau levels quantization can follow directly from the
existence of a topological winding number. The microscopic computation of the
current can then be performed within the Keldysh formalism in a systematic way
at finite magnetic fields $B$ (i.e. beyond the semi-classical limit $B =
\infty$). The formalism allows us to define a general vortex current density as
long as the gradient expansion theory is applicable. As a result, the total
current is expressed in terms of edge contributions only. We obtain the first
and third lowest order contributions to the current due to Landau-levels mixing
processes, and derive in a transparent way the quantization of the Hall
conductance. Finally, we point out qualitatively the importance of
inhomogeneities of the vortex density to capture the dissipative longitudinal
transport.

16
The categories of this paper are: stat
23
The categories of this paper are: solv-int
30
The categories of this paper are: q-alg
21
The categories of this paper are: adap-org
32
The categories of this paper are: atom-ph
1
The categories of this paper are: cs
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
19
The categories of this paper are: eess
6
The categories of this paper are: astro-ph
37
The categories of this paper are: supr-con
25
The categories of this paper are: patt-sol
3
The categories of this paper are: physics
11
The categories of this paper are: hep-lat
13
The categories of this paper are: quant-ph