Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Metastable superpositions of ortho- and para-Helium states   We analyze superpositions of ortho- and para-Helium states, considering the
possible existence of stationary and metastable states in the system. In
particular, the metastable superposition of 1s2s ortho and para states seems to
be accessible to experimental scrutiny.

3
The categories of this paper are: physics
26
The categories of this paper are: bayes-an
18
The categories of this paper are: econ
32
The categories of this paper are: atom-ph
1
The categories of this paper are: cs
28
The categories of this paper are: alg-geom
2
The categories of this paper are: math
27
The categories of this paper are: comp-gas
6
The categories of this paper are: astro-ph
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
8
The categories of this paper are: hep-ex
16
The categories of this paper are: stat
29
The categories of this paper are: funct-an
17
The categories of this paper are: q-fin
31
The categories of this paper are: ao-sci