Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Manipulation and exchange of Light with Orbital Angular Momentum in
  Quantum Dot Molecules   We study the interaction of laser pulses carrying orbital angular momentum
(OAM) with structural asymmetry quantum dot molecules characterized by four
energy levels. We demonstrate how the inter-dot tunneling endows exchange of
optical vortices between different frequencies. We consider a case where a weak
probe beam has an optical vortex and thus has a zero intensity at the center.
The presence of tunneling coupling generates an additional weak laser beam with
the same vorticity as that of the incident vortex beam. We analyze conditions
for the vortex of the initial beam to be transferred efficiently to the
generated beam. The propagation of Laguerre-Gaussian (LG) beams possessing OAM
states characterized by both azimuthal and radial indices is then investigated
for the case where the strong control beam is also an OAM mode. It is shown
that the conservation of OAM states is always satisfied over the OAM exchange
process. Yet, an abnormal case is observed in which the radial index induces
some intensity patterns of the generated beam which differs from a pure LG beam
of incident beams. Analytical solutions are provided to elucidate such effects
induced by radial indices on propagation characteristics of OAM beams. When
superimposing two initially present weak OAM modes, it is observed that the
resulting optical vortices move about the beam axis as the light propagates,
forming a sort of "constellation" around the center. The shift in axis of such
a composite pulses is due to the effect of inter-dot tunneling which is
controlled by an external electric voltage. The optical angular momenta may add
a new degree of freedom in the study of solid systems suitable for quantum
technologies.

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The categories of this paper are: acc-phys
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The categories of this paper are: q-fin
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The categories of this paper are: nlin
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The categories of this paper are: gr-qc
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The categories of this paper are: stat
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The categories of this paper are: q-bio
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The categories of this paper are: funct-an
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The categories of this paper are: hep-ex
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The categories of this paper are: comp-gas
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The categories of this paper are: bayes-an
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The categories of this paper are: supr-con
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: cond-mat
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The categories of this paper are: dg-ga