Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Shift and broadening of resonance lines of antiprotonic helium atoms in
  solid helium   We have estimated the shift and broadening of the resonance lines in the
spectrum of antiprotonic helium atoms $\bar{p}\mathrm{He}^{+}$ implanted in
solid helium $^4$He. The application of the response function for crystalline
helium has enabled determination of the contributions from the collective
degrees of freedom to the shift and broadening. It occurs that the broadening
due to the collective motion is negligible compared to the natural line width.
The available pair-correlation functions for crystalline $^4$He have been
applied for estimating the resonance-line shift due to collisions of
$\bar{p}\mathrm{He}^{+}$ atom with the surrounding $^4$He atoms. The dependence
of the line shift, which has been calculated in the quasistatic limit, on the
solid-$^4$He density is nonlinear.

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The categories of this paper are: q-fin
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The categories of this paper are: econ
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The categories of this paper are: astro-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: nlin
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The categories of this paper are: q-bio
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The categories of this paper are: adap-org
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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: cond-mat
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The categories of this paper are: stat
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The categories of this paper are: math
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The categories of this paper are: nucl-ex
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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: acc-phys