Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Experimental Verification of Position-Dependent Angular-Momentum
  Selection Rules for Absorption of Twisted Light by a Bound Electron   We analyze the multipole excitation of atoms with twisted light, i.e., by a
vortex light field that carries orbital angular momentum. A single trapped
$^{40}$Ca$^+$ ion serves as a localized and positioned probe of the exciting
field. We drive the $S_{1/2} \to D_{5/2}$ transition and observe the relative
strengths of different transitions, depending on the ion's transversal position
with respect to the center of the vortex light field. On the other hand,
transition amplitudes are calculated for a twisted light field in form of a
Bessel beam, a Bessel-Gauss and a Gauss-Laguerre mode. Analyzing experimental
obtained transition amplitudes we find agreement with the theoretical
predictions at a level of better than 3\%. Finally, we propose measurement
schemes with two-ion crystals to enhance the sensing accuracy of vortex modes
in future experiments.

8
The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
12
The categories of this paper are: nucl-th
7
The categories of this paper are: hep-th
9
The categories of this paper are: nlin
1
The categories of this paper are: cs
24
The categories of this paper are: dg-ga
17
The categories of this paper are: q-fin
0
The categories of this paper are: hep-ph
30
The categories of this paper are: q-alg
10
The categories of this paper are: q-bio
21
The categories of this paper are: adap-org
32
The categories of this paper are: atom-ph
11
The categories of this paper are: hep-lat
36
The categories of this paper are: cmp-lg
22
The categories of this paper are: chao-dyn