Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nd$^+$ isotope shift measurements in a cryogenically-cooled neutral
  plasma   We report measurements of the isotope shifts of two transitions
($4f^46s\rightarrow [25044.7]^{\circ}_{7/2}$ and $4f^46s\rightarrow
[25138.6]^{\circ}_{7/2}$) in neodymium ions (Nd$^+$) with hundredfold improved
accuracy, using laser spectroscopy of a cryogenically-cooled neutral plasma.
The isotope shifts were measured across a set of five spin-zero isotopes that
spans a nuclear shape transition. We discuss the prospects for further
improvements to the accuracy of Nd$^+$ isotope shifts using optical clock
transitions, which could enable higher precision tests of King plot linearity
for new physics searches.

8
The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
19
The categories of this paper are: eess
17
The categories of this paper are: q-fin
2
The categories of this paper are: math
18
The categories of this paper are: econ
11
The categories of this paper are: hep-lat
7
The categories of this paper are: hep-th
31
The categories of this paper are: ao-sci
23
The categories of this paper are: solv-int
36
The categories of this paper are: cmp-lg
21
The categories of this paper are: adap-org
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The categories of this paper are: cond-mat
1
The categories of this paper are: cs
29
The categories of this paper are: funct-an
6
The categories of this paper are: astro-ph