Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Measuring ion oscillations at the quantum level with fluorescence light   We demonstrate an optical method for detecting the mechanical oscillations of
an atom with single-phonon sensitivity. The measurement signal results from the
interference between the light scattered by a single trapped atomic ion and
that of its mirror image. The motion of the atom modulates the interference
path length and hence the photon detection rate. We detect the oscillations of
the atom in the Doppler cooling limit and reconstruct average trajectories in
phase space. We demonstrate single-phonon sensitivity near the ground state of
motion after EIT cooling. These results could be applied for motion detection
of other light scatterers of fundamental interest, such as trapped
nanoparticles.

29
The categories of this paper are: funct-an
32
The categories of this paper are: atom-ph
17
The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
4
The categories of this paper are: cond-mat
19
The categories of this paper are: eess
35
The categories of this paper are: mtrl-th
1
The categories of this paper are: cs
7
The categories of this paper are: hep-th
2
The categories of this paper are: math
15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol
30
The categories of this paper are: q-alg
28
The categories of this paper are: alg-geom
10
The categories of this paper are: q-bio