Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Critical Ambient Pressure and Critical Cooling Rate in Optomechanics of
  Electromagnetically Levitated Nanoparticles   The concept of critical ambient pressure is introduced. The particle escapes
from its trap when the ambient pressure becomes comparable with or smaller than
a critical value, even if the particle motion is cooled by one of the feedback
(or cavity) cooling schemes realized so far. The critical ambient pressure may
be so small that it is not a limiting factor in ground-state cooling, but
critical feedback cooling rates, which are also introduced, are limiting
factors. The particle escapes from its trap if any of the feedback cooling
rates becomes comparable with or larger than its critical value. Critical
feedback cooling rate is different from the well-known manifestation of the
measurement noise. The critical feedback cooling rate corresponding to a
certain component of the particle motion is usually smaller than the optimum
feedback cooling rate at which the standard quantum limit happens unless that
component is cooled by the Coulomb force (instead of the optical gradient
force). Also, given that the measurement noise for the z component is smaller
than the measurement noises for the other two components (assuming that the
beam illuminating the particle for photodetection propagates parallel to the z
axis), the feedback scheme in which the z component of the particle motion is
cooled by the Coulomb force has the best performance. This conclusion is in
agreement with the experimental results published after writing the first
version of this paper. The dependence of the critical ambient pressure, the
critical feedback cooling rates, and the minimum achievable mean phonon numbers
on the parameters of the system is derived, and can be verified experimentally.
The insights into and the subtle points about the EM force, the EM force
fluctuations, and the measurement noise that are presented might be useful in
many systems besides those examined here.

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The categories of this paper are: hep-th
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The categories of this paper are: hep-ph
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The categories of this paper are: solv-int
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The categories of this paper are: q-fin
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The categories of this paper are: q-bio
33
The categories of this paper are: plasm-ph
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The categories of this paper are: cs
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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-ex
34
The categories of this paper are: chem-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: econ
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The categories of this paper are: atom-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-lat
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The categories of this paper are: cond-mat