Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Relativistic energy shifts in Ge II, Sn II and Pb II and search for
  cosmological variation of the fine structure constant   Sensitivity of atomic transition frequencies to variation of the fine
structure constant $\alpha=e^2/\hbar c$ increases proportional to $Z^2$ where
$Z$ is the nuclear charge. Recently several lines of heavy ions Ge II, Sn II
and Pb II have been detected in quasar absorption spectra. We have performed
accurate many-body calculations of $\alpha^2$-dependence of transition
frequencies ($q$-coefficients) for these atoms and found an order of magnitude
increase in sensitivity in comparison with atomic transitions which were
previously used to search for temporal and spatial variation of $\alpha$ in
quasar absorption systems. An interesting feature in Pb II is highly non-linear
dependence on $\alpha^2$ due to the level pseudo-crossings.

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The categories of this paper are: hep-lat
29
The categories of this paper are: funct-an
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The categories of this paper are: atom-ph
0
The categories of this paper are: hep-ph
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The categories of this paper are: comp-gas
20
The categories of this paper are: acc-phys
4
The categories of this paper are: cond-mat
5
The categories of this paper are: gr-qc
17
The categories of this paper are: q-fin
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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: plasm-ph
26
The categories of this paper are: bayes-an
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The categories of this paper are: stat
36
The categories of this paper are: cmp-lg
25
The categories of this paper are: patt-sol