Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Guiding neutral polar molecules by electromagnetic vortex field --- a
  classical approach   It is shown, within classical mechanics, that the field of an electromagnetic
vortex is capable of capturing and guiding neutral molecules endowed with a
permanent electric dipole moment (PEDM). Similarly as in the case of the
magnetic field applied to elementary particles or atoms, this effect turns out
to be very delicate because of the small values of PEDM observed in real
molecules. They amount to $2\times10^{5}\, e{\mathrm{fm}}$ (electron charge
$\times$ fermi) or less, which requires the use of very strong electric fields.
It has also been observed that there exists a threshold in field strength above
which the particles are ejected from the trap. Trajectories of guided particles
are usually quite chaotic, which is a consequence of non-linearity of the
equations of motion. With a very special and precise adjustment of parameters,
a regular (i.e., circular, in the transverse plane) trajectory can be obtained.
The presence of an additional constant electric field pointing along the
direction of the wave propagation might help to achieve the necessary tuning
and realize such trajectories.

11
The categories of this paper are: hep-lat
19
The categories of this paper are: eess
23
The categories of this paper are: solv-int
14
The categories of this paper are: math-ph
15
The categories of this paper are: nucl-ex
20
The categories of this paper are: acc-phys
8
The categories of this paper are: hep-ex
29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
12
The categories of this paper are: nucl-th
31
The categories of this paper are: ao-sci
32
The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
2
The categories of this paper are: math
6
The categories of this paper are: astro-ph