Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Search for Variations of Fundamental Constants using Atomic Fountain
  Clocks   Over five years we have compared the hyperfine frequencies of 133Cs and 87Rb
atoms in their electronic ground state using several laser cooled 133Cs and
87Rb atomic fountains with an accuracy of ~10^{-15}. These measurements set a
stringent upper bound to a possible fractional time variation of the ratio
between the two frequencies : (d/dt)ln(nu_Rb/nu_Cs)=(0.2 +/- 7.0)*10^{-16}
yr^{-1} (1 sigma uncertainty). The same limit applies to a possible variation
of the quantity (mu_Rb/mu_Cs)*alpha^{-0.44}, which involves the ratio of
nuclear magnetic moments and the fine structure constant.

29
The categories of this paper are: funct-an
28
The categories of this paper are: alg-geom
36
The categories of this paper are: cmp-lg
14
The categories of this paper are: math-ph
21
The categories of this paper are: adap-org
33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
37
The categories of this paper are: supr-con
7
The categories of this paper are: hep-th
1
The categories of this paper are: cs
4
The categories of this paper are: cond-mat
9
The categories of this paper are: nlin
19
The categories of this paper are: eess
24
The categories of this paper are: dg-ga
25
The categories of this paper are: patt-sol