Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Possible Constraints on the Time Variation of the Fine Structure
  Constant from Cosmic Microwave Background Data   The formation of the cosmic microwave background radiation (CMBR) provides a
very powerful probe of the early universe at the epoch of recombination.
Specifically, it is possible to constrain the variation of fundamental physical
constants in the early universe. We have calculated the effect of a varying
electromagnetic coupling constant (\alpha) on the CMBR and find that new
satellite experiments should provide a tight constraint on the value of \alpha
at recombination which is complementary to existing constraints. An estimate of
the obtainable precision is |\dot{\alpha}/\alpha| \leq 7 x 10^{-13} y^{-1} in a
realistic experiment.

31
The categories of this paper are: ao-sci
16
The categories of this paper are: stat
27
The categories of this paper are: comp-gas
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The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
1
The categories of this paper are: cs
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The categories of this paper are: q-fin
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The categories of this paper are: chem-ph
5
The categories of this paper are: gr-qc
20
The categories of this paper are: acc-phys
2
The categories of this paper are: math
24
The categories of this paper are: dg-ga
4
The categories of this paper are: cond-mat
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The categories of this paper are: econ
21
The categories of this paper are: adap-org
10
The categories of this paper are: q-bio