Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spin beats in the photoluminescence polarization dynamics of charged
  excitons in InP/(In,Ga)P quantum dots in presence of nuclear quadrupole
  interaction   The spin dynamics of positively (X$^{+}$) and negatively (X$^{-}$) charged
excitons in InP/In$_{0.48}$Ga$_{0.52}$P quantum dots subject to a magnetic
field is studied. We find that a characteristic feature of the system under
study is the presence of nuclear quadrupole interaction, which leads to
stabilization of the nuclear and electron spins in a quantum dot in zero
external magnetic field. In detail, the nuclear quadrupole interaction leads to
pinning of the Overhauser field along the quadrupole axis, which is close to
the growth axis of the heterostructure. The nuclear effects are observed only
when resident electrons are confined in the quantum dots, i.e. for X$^{-}$
trion photoexcitation. The presence of X$^{-}$ and X$^{+}$ trion contributions
to the photoluminescence together with the quadrupole interaction significantly
affects the dynamics of optical orientation in Voigt magnetic field. In absence
of dynamic nuclear spin polarization the time evolution of the
photoluminescence polarization was fitted by a form which describes the
electron spin relaxation in "frozen" nuclear field fluctuations. In relatively
large external magnetic fields exceeding 60 mT good agreement between theory
and experiment is achieved.

12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
2
The categories of this paper are: math
24
The categories of this paper are: dg-ga
8
The categories of this paper are: hep-ex
34
The categories of this paper are: chem-ph
16
The categories of this paper are: stat
17
The categories of this paper are: q-fin
6
The categories of this paper are: astro-ph
1
The categories of this paper are: cs
33
The categories of this paper are: plasm-ph
11
The categories of this paper are: hep-lat
29
The categories of this paper are: funct-an
32
The categories of this paper are: atom-ph