Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum Monte Carlo simulation of spin-polarized H   The ground-state properties of spin polarized hydrogen H$\downarrow$ are
obtained by means of diffusion Monte Carlo calculations. Using the most
accurate to date ab initio H$\downarrow$-H$\downarrow$ interatomic potential we
have studied its gas phase, from the very dilute regime until densities above
its freezing point. At very small densities, the equation of state of the gas
is very well described in terms of the gas parameter $\rho a^3$, with $a$ the
s-wave scattering length. The solid phase has also been studied up to high
pressures. The gas-solid phase transition occurs at a pressure of 173 bar, a
much higher value than suggested by previous approximate descriptions.

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The categories of this paper are: stat
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The categories of this paper are: econ
31
The categories of this paper are: ao-sci
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The categories of this paper are: eess
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The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: math-ph
37
The categories of this paper are: supr-con
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The categories of this paper are: adap-org
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The categories of this paper are: solv-int
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The categories of this paper are: alg-geom
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The categories of this paper are: astro-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: comp-gas