Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Onset temperature of Bose-Einstein condensation in incommensurate solid
  4He   The temperature dependence of the one-body density matrix in 4He crystals
presenting vacancies is computed with Path Integral Monte Carlo. The main
purpose of this study is to estimate the onset temperature T_0 of Bose-Einstein
condensation in these systems. We see that T_0 depends on the vacancy
concentration X_v of the simulated system, but not following the law $T_0 \sim
X_v^{2/3}$ obtained assuming non-interacting vacancies. For the lowest X_v we
have studied, that is X_v = 1/256, we get T_0 = (0.15 \pm 0.05) K, close to the
temperatures at which a finite fraction of non-classical rotational inertia is
experimentally observed. Below T_0, vacancies do not act as classical point
defects becoming completely delocalized entities.

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The categories of this paper are: funct-an
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The categories of this paper are: mtrl-th
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The categories of this paper are: math-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: q-bio
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The categories of this paper are: solv-int
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The categories of this paper are: nucl-ex
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The categories of this paper are: atom-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: econ
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The categories of this paper are: supr-con
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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: chao-dyn
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The categories of this paper are: physics