Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Shelving spectroscopy of the strontium intercombination line   We present a spectroscopy scheme for the 7-kHz-wide 689-nm intercombination
line of strontium. We rely on shelving detection, where electrons are first
excited to a metastable state by the spectroscopy laser before their state is
probed using the broad transition at 461 nm. As in the similar setting of
calcium beam clocks, this enhances dramatically the signal strength as compared
to direct saturated fluorescence or absorption spectroscopy of the narrow line.
We implement shelving spectroscopy both in directed atomic beams and hot vapor
cells with isotropic atomic velocities. We measure a fractional frequency
instability $\sim 2 \times 10^{-12}$ at 1 s limited by technical noise - about
one order of magnitude above shot noise limitations for our experimental
parameters. Our work illustrates the robustness and flexibility of a scheme
that can be very easily implemented in the reference cells or ovens of most
existing strontium experiments, and may find applications for low-complexity
clocks.

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The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
6
The categories of this paper are: astro-ph
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The categories of this paper are: acc-phys
23
The categories of this paper are: solv-int
33
The categories of this paper are: plasm-ph
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The categories of this paper are: chem-ph
1
The categories of this paper are: cs
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The categories of this paper are: supr-con
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The categories of this paper are: hep-th
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The categories of this paper are: hep-lat
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The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
18
The categories of this paper are: econ
32
The categories of this paper are: atom-ph