Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Two-Symmetry Penning-Ioffe Trap for Antihydrogen Cooling and
  Spectroscopy   High-accuracy spectroscopic comparisons of trapped antihydrogen atoms
($\overline{\text{H}}$) and hydrogen atoms ($\text{H}$) promise to stringently
test the fundamental CPT symmetry invariance of the standard model of particle
physics. ATRAP's nested Penning-Ioffe trap was developed for such studies. The
first of its unique features is that its magnetic Ioffe trap for
$\overline{\text{H}}$ atoms can be switched between quadrupole and octupole
symmetries. The second is that it allows laser and microwave access
perpendicular to the central axis of the traps.

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The categories of this paper are: cs
31
The categories of this paper are: ao-sci
12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex
27
The categories of this paper are: comp-gas
13
The categories of this paper are: quant-ph
20
The categories of this paper are: acc-phys
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The categories of this paper are: q-fin
6
The categories of this paper are: astro-ph
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ
36
The categories of this paper are: cmp-lg
24
The categories of this paper are: dg-ga
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The categories of this paper are: eess
23
The categories of this paper are: solv-int
30
The categories of this paper are: q-alg