Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A molecular superfluid: non-classical rotations in doped para-hydrogen
  clusters   Clusters of para-hydrogen (pH2) have been predicted to exhibit superfluid
behavior, but direct observation of this phenomenon has been elusive. Combining
experiments and theoretical simulations, we have determined the size evolution
of the superfluid response of pH2 clusters doped with carbon dioxide (CO2).
Reduction of the effective inertia is observed when the dopant is surrounded by
the pH2 solvent. This marks the onset of molecular superfluidity in pH2. The
fractional occupation of solvation rings around CO2 correlates with enhanced
superfluid response for certain cluster sizes.

12
The categories of this paper are: nucl-th
4
The categories of this paper are: cond-mat
20
The categories of this paper are: acc-phys
26
The categories of this paper are: bayes-an
36
The categories of this paper are: cmp-lg
27
The categories of this paper are: comp-gas
23
The categories of this paper are: solv-int
6
The categories of this paper are: astro-ph
28
The categories of this paper are: alg-geom
33
The categories of this paper are: plasm-ph
32
The categories of this paper are: atom-ph
30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
18
The categories of this paper are: econ
0
The categories of this paper are: hep-ph
1
The categories of this paper are: cs