Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spatial structure of neutron Cooper pair in low density uniform matter   We analyze spatial structure of the neutron Cooper pair in superfluid
low-density uniform matter by means of BCS calculations employing a bare force
and the effective Gogny interaction. It is shown that the Cooper pair exhibits
a strong spatial di-neutron correlation in a wide range of neutron density
$\rho/\rho_0\approx 10^{-4}-0.5$. This feature is related to the crossover
behavior between the pairing of the weak coupling BCS type and the
Bose-Einstein condensation of bound neutron pairs. We also show that the
zero-range delta interaction can describe the spatial structure of the neutron
Cooper pair if the density dependent interaction strength and the cut-off
energy are appropriately chosen. Parameterizations of the density-dependent
delta interaction satisfying this condition are discussed.

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The categories of this paper are: acc-phys
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The categories of this paper are: adap-org
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The categories of this paper are: hep-ph
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The categories of this paper are: physics
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The categories of this paper are: comp-gas
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The categories of this paper are: atom-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: cond-mat
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The categories of this paper are: astro-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-ex
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The categories of this paper are: nlin
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The categories of this paper are: hep-lat
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The categories of this paper are: chem-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: stat