Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnetoresistance of a 2D electron gas caused by electron interactions
  in the transition from the diffusive to the ballistic regime   On a high-mobility 2D electron gas we have observed, in strong magnetic
fields (omega_{c} tau > 1), a parabolic negative magnetoresistance caused by
electron-electron interactions in the regime of k_{B} T tau / hbar ~ 1, which
is the transition from the diffusive to the ballistic regime. From the
temperature dependence of this magnetoresistance the interaction correction to
the conductivity delta sigma_{xx}^{ee}(T) is obtained in the situation of a
long-range fluctuation potential and strong magnetic field. The results are
compared with predictions of the new theory of interaction-induced
magnetoresistance.

36
The categories of this paper are: cmp-lg
25
The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
11
The categories of this paper are: hep-lat
28
The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc
2
The categories of this paper are: math
6
The categories of this paper are: astro-ph
24
The categories of this paper are: dg-ga
8
The categories of this paper are: hep-ex
3
The categories of this paper are: physics
0
The categories of this paper are: hep-ph
30
The categories of this paper are: q-alg
29
The categories of this paper are: funct-an
33
The categories of this paper are: plasm-ph