Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Phase transitions in a system of indirect magnetoexcitons in coupled
  quantum wells at high magnetic field: the role of disorder   Collective properties of a quasi-two-dimensional (2D) system of spatially
indirect magnetoexcitons in coupled quantum wells (CQW) in high magnetic field
$H$ were analyzed in the presence of disorder. The Hamiltonian of the dilute
gas of magnetoexcitons with dipole-dipole repulsion in a random field has been
reduced to the Hamiltonian of a dilute gas of dipolar excitons without an
applied magnetic field, but in an $H$-dependent effective random field and
having an effective mass of magnetoexciton which is a function of the magnetic
field and parameters of the CQW. For 2D magnetoexcitonic systems, the increase
of the magnetic field $H$ and the interwell distance $D$ is found to increase
the effective renormalized random field parameter $Q$ and suppress the
superfluid density $n_s$ and the temperature of the Kosterlitz-Thouless
transition $T_c$. It is shown that in the presence of the disorder there is a
quantum transition to the superfluid state at zero temperature T=0 with respect
to the magnetic field $H$ and the parameters of the disorder. There is no
superfluidity at any exciton density in the presence of the disorder at
sufficiently large magnetic field $H$ or sufficiently large disorder.

29
The categories of this paper are: funct-an
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
28
The categories of this paper are: alg-geom
8
The categories of this paper are: hep-ex
18
The categories of this paper are: econ
10
The categories of this paper are: q-bio
14
The categories of this paper are: math-ph
6
The categories of this paper are: astro-ph
7
The categories of this paper are: hep-th
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
27
The categories of this paper are: comp-gas
16
The categories of this paper are: stat
25
The categories of this paper are: patt-sol
22
The categories of this paper are: chao-dyn