Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Precise frequency measurements of atomic transitions using a
  Rb-stabilized resonator   We demonstrate a technique for frequency measurements of atomic transitions
with a precision of 30 kHz. The frequency is measured using a ring-cavity
resonator whose length is calibrated against a reference laser locked to the
$D_2$ line of $^{87}$Rb, the frequency of which is known to 10 kHz. We have
used this to measure the hyperfine structure in the $5P_{3/2}$ state of
$^{85}$Rb. We obtain precise values for the hyperfine constants $A=25.041(6)$
MHz and $B=26.013(25)$ MHz, and a value of 77.992(20) MHz for the isotope shift
in the $D_2$ line.

36
The categories of this paper are: cmp-lg
35
The categories of this paper are: mtrl-th
15
The categories of this paper are: nucl-ex
17
The categories of this paper are: q-fin
24
The categories of this paper are: dg-ga
29
The categories of this paper are: funct-an
6
The categories of this paper are: astro-ph
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
5
The categories of this paper are: gr-qc
4
The categories of this paper are: cond-mat
14
The categories of this paper are: math-ph
28
The categories of this paper are: alg-geom
22
The categories of this paper are: chao-dyn
12
The categories of this paper are: nucl-th
19
The categories of this paper are: eess