Absolute frequency measurement of the 40Ca+ clock transition using a GNSS link to the SI second
Abstract
We report the absolute frequency measurement of the 4s $ ^{2}S_{1/2}\leftrightarrow 3d$ 2D5/2 40Ca+ clock transition with respect to the SI second. To perform this measurement, a link between our laboratory in Innsbruck and the clocks realizing the Coordinated Universal Time at the Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig was installed and characterized using the Global Navigation Satellite System GNSS. The comparison between our clock and the ones at PTB was done using the Precise Point Positioning technique. After the evaluation of the systematic shifts, the measured transition frequency is 411 042 129 776 401.2±0.6 Hz with a fractional uncertainty of 1.5 × 10−15. The stability of the clock measurements was also corroborated by comparing two different calcium ion clock experiments, which share the clock laser source at our institute. Furthermore, after careful evaluation of the trap-drive induced ac magnetic fields, we estimate ac Zeeman shifts on the D5/2 sublevels and reevaluate the Landé g-factor of the 3d 2D5/2 level to be g5/2= 1.200329(1).
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BibTeX
@misc{guevarabertsch2026absolute,
title = {{Absolute frequency measurement of the $^40$Ca$^+$ clock transition using a GNSS link to the SI second}},
author = {M. Guevara-Bertsch and M. K. Joshi and M. I Hussain and R. Blatt and C. F. Roos},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.15844},
eprint = {2609.15844},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.15844},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Absolute frequency measurement of the ^40Ca^+ clock transition using a GNSS link to the SI second
AU - M. Guevara-Bertsch
AU - M. K. Joshi
AU - M. I Hussain
AU - R. Blatt
AU - C. F. Roos
PY - 2026
DA - 2026/09/17
PB - arXiv
DO - 10.48550/arxiv.2609.15844
UR - https://arxiv.org/abs/2609.15844
AB - We report the absolute frequency measurement of the 4s $ ^{2}S_{1/2}\leftrightarrow 3d$ ^2D_5/2 ^40Ca^+ clock transition with respect to the SI second. To perform this measurement, a link between our laboratory in Innsbruck and the clocks realizing the Coordinated Universal Time at the Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig was installed and characterized using the Global Navigation Satellite System GNSS. The comparison between our clock and the ones at PTB was done using the Precise Point Positioning technique. After the evaluation of the systematic shifts, the measured transition frequency is 411 042 129 776 401.2±0.6 Hz with a fractional uncertainty of 1.5 × 10^−15. The stability of the clock measurements was also corroborated by comparing two different calcium ion clock experiments, which share the clock laser source at our institute. Furthermore, after careful evaluation of the trap-drive induced ac magnetic fields, we estimate ac Zeeman shifts on the D_5/2 sublevels and reevaluate the Landé g-factor of the 3d ^2D_5/2 level to be g_5/2= 1.200329(1).
ER -