Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Weighing an optically trapped microsphere in thermal equilibrium with
  air   We report a weighing metrology experiment of a single silica microsphere
optically trapped and immersed in air. Based on fluctuations about thermal
equilibrium, three different mass measurements are investigated, each arising
from one of two principle methods. The first method is based on spectral
analysis and enables simultaneous extraction of various system parameters.
Additionally, the spectral method yields a mass measurement with systematic
relative uncertainty of 3.0\% in 3~s and statistical relative uncertainty of
0.9\% across several trapping laser powers. Parameter values learned from the
spectral method serve as input, or a calibration step, for the second method
based on the equipartition theorem. The equipartition method gives two
additional mass measurements with systematic and statistical relative
uncertainties slightly larger than the ones obtained in the spectral method,
but over a time interval 10 times shorter. Our mass estimates, which are
obtained in a scenario of strong environmental coupling, have uncertainties
comparable to ones obtained in force-driven metrology experiments with
nanospheres in vacuum. Moreover, knowing the microsphere's mass accurately and
precisely will enable air-based sensing applications.

15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
0
The categories of this paper are: hep-ph
20
The categories of this paper are: acc-phys
2
The categories of this paper are: math
34
The categories of this paper are: chem-ph
4
The categories of this paper are: cond-mat
24
The categories of this paper are: dg-ga
11
The categories of this paper are: hep-lat
8
The categories of this paper are: hep-ex
27
The categories of this paper are: comp-gas
17
The categories of this paper are: q-fin
6
The categories of this paper are: astro-ph
28
The categories of this paper are: alg-geom
12
The categories of this paper are: nucl-th
26
The categories of this paper are: bayes-an