Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Superfluidity and Quantum Melting of para-Hydrogen clusters   Structural and superfluid properties of para-Hydrogen clusters of size up to
N=40 molecules, are studied at low temperature (0.5 K < T < 4 K) by Path
Integral Monte Carlo simulations. The superfluid fraction displays an
interesting, non-monotonic behavior for 22 < N < 30. We interpret this
dependence in terms of variations with N of the cluster structure.
Superfluidity is observed at low T in clusters of as many as 27 molecules; in
the temperature range considered here, quantum melting is observed in some
clusters, which freeze at high temperature.

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The categories of this paper are: patt-sol
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The categories of this paper are: gr-qc
27
The categories of this paper are: comp-gas
1
The categories of this paper are: cs
15
The categories of this paper are: nucl-ex
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The categories of this paper are: bayes-an
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-th
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The categories of this paper are: hep-lat
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The categories of this paper are: quant-ph
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The categories of this paper are: physics
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The categories of this paper are: solv-int
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The categories of this paper are: astro-ph
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The categories of this paper are: mtrl-th
12
The categories of this paper are: nucl-th
18
The categories of this paper are: econ