Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Scanning force sensing at $\mu$m-distances from a conductive surface
  with nanospheres in an optical lattice   The center-of-mass motion of optically trapped dielectric nanoparticles in
vacuum is extremely well-decoupled from its environment, making a powerful tool
for measurements of feeble sub-attonewton forces. We demonstrate a method to
trap and manuever nanoparticles in an optical standing wave potential formed by
retro-reflecting a laser beam from a metallic mirror surface. We can reliably
position a $\sim 170$ nm diameter silica nanoparticle at distances of a few
hundred nanometers to tens of microns from the surface of a gold-coated silicon
mirror by transferring it from a single-beam tweezer trap into the standing
wave potential. We can further scan the two dimensional space parallel to the
mirror surface by using a piezo-driven mirror. This method enables
three-dimensional scanning force sensing near surfaces using optically trapped
nanoparticles, promising for high-sensitivity scanning force microscopy, tests
of the Casimir effect, and tests of the gravitational inverse square law at
micron scales.

27
The categories of this paper are: comp-gas
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The categories of this paper are: q-alg
36
The categories of this paper are: cmp-lg
34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
18
The categories of this paper are: econ
9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
26
The categories of this paper are: bayes-an
14
The categories of this paper are: math-ph
15
The categories of this paper are: nucl-ex
21
The categories of this paper are: adap-org
7
The categories of this paper are: hep-th
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The categories of this paper are: eess
25
The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th