Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Controlling the net charge on a nanoparticle optically levitated in
  vacuum   Optically levitated nanoparticles in vacuum are a promising model system to
test physics beyond our current understanding of quantum mechanics. Such
experimental tests require extreme control over the dephasing of the levitated
particle's motion. If the nanoparticle carries a finite net charge, it
experiences a random Coulomb force due to fluctuating electric fields. This
dephasing mechanism can be fully excluded by discharging the levitated
particle. Here, we present a simple and reliable technique to control the
charge on an optically levitated nanoparticle in vacuum. Our method is based on
the generation of charges in an electric discharge and does not require
additional optics or mechanics close to the optical trap.

18
The categories of this paper are: econ
10
The categories of this paper are: q-bio
6
The categories of this paper are: astro-ph
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
13
The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol
30
The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
4
The categories of this paper are: cond-mat
5
The categories of this paper are: gr-qc
19
The categories of this paper are: eess
16
The categories of this paper are: stat
22
The categories of this paper are: chao-dyn
20
The categories of this paper are: acc-phys
37
The categories of this paper are: supr-con