Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ab Initio Equation of State for Hydrogen-Helium Mixtures with
  Recalibration of the Giant-Planet Mass-Radius Relation   Using density functional molecular dynamics simulations, we determine the
equation of state for hydrogen-helium mixtures spanning density-temperature
conditions typical of giant planet interiors, ~0.2-9 g/cc and 1000-80000 K for
a typical helium mass fraction of 0.245. In addition to computing internal
energy and pressure, we determine the entropy using an ab initio thermodynamic
integration technique. A comprehensive equation of state (EOS) table with 391
density-temperature points is constructed and the results are presented in form
of two-dimensional free energy fit for interpolation. Deviations between our ab
initio EOS and the semi-analytical EOS model by Saumon and Chabrier are
analyzed in detail, and we use the results for initial revision of the inferred
thermal state of giant planets with known values for mass and radius. Changes
are most pronounced for planets in the Jupiter mass range and below. We present
a revision to the mass-radius relationship which makes the hottest exoplanets
increase in radius by ~0.2 Jupiter radii at fixed entropy and for masses
greater than ~0.5 Jupiter mass. This change is large enough to have possible
implications for some discrepant "inflated giant exoplanets".

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The categories of this paper are: nucl-ex
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The categories of this paper are: alg-geom
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The categories of this paper are: quant-ph
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The categories of this paper are: funct-an
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The categories of this paper are: econ
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The categories of this paper are: hep-ex
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The categories of this paper are: cmp-lg
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The categories of this paper are: nucl-th
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The categories of this paper are: physics
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The categories of this paper are: dg-ga
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The categories of this paper are: chem-ph
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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: supr-con
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The categories of this paper are: atom-ph
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The categories of this paper are: bayes-an