Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Preparation of circular Rydberg states in helium using the crossed
  fields method   Helium atoms have been prepared in the circular
$|n=55,\ell=54,m_{\ell}=+54\rangle$ Rydberg state using the crossed electric
and magnetic fields method. The atoms, initially travelling in pulsed
supersonic beams, were photoexcited from the metastable $1s2s\,^3S_1$ level to
the outermost, $m_{\ell}=0$ Rydberg-Stark state with $n=55$ in the presence of
a strong electric field and weak perpendicular magnetic field. Following
excitation, the electric field was adiabatically switched off causing the atoms
to evolve into the circular state with $m_{\ell}=+54$ defined with respect to
the magnetic field quantization axis. The circular states were detected by
ramped electric field ionization along the magnetic field axis. The dependence
of the circular state production efficiency on the strength of the excitation
electric field, and the electric-field switch-off time was studied, and
microwave spectroscopy of the circular-to-circular
$|55,54,+54\rangle\rightarrow|56,55,+55\rangle$ transition at $\sim38.5$~GHz
was performed.

24
The categories of this paper are: dg-ga
1
The categories of this paper are: cs
18
The categories of this paper are: econ
14
The categories of this paper are: math-ph
2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
30
The categories of this paper are: q-alg
26
The categories of this paper are: bayes-an
27
The categories of this paper are: comp-gas
20
The categories of this paper are: acc-phys
12
The categories of this paper are: nucl-th
36
The categories of this paper are: cmp-lg
34
The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
13
The categories of this paper are: quant-ph