1. An $^{115}$In$^+$-$^{172}$Yb$^+$ Coulomb crystal clock with $2.5\times10^{-18}$ systematic uncertainty
- Author
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Hausser, H. N., Keller, J., Nordmann, T., Bhatt, N. M., Kiethe, J., Liu, H., von Boehn, M., Rahm, J., Weyers, S., Benkler, E., Lipphardt, B., Doerscher, S., Stahl, K., Klose, J., Lisdat, C., Filzinger, M., Huntemann, N., Peik, E., and Mehlstäubler, T. E.
- Subjects
Physics - Atomic Physics ,Quantum Physics - Abstract
We present a scalable mixed-species Coulomb crystal clock based on the $^1S_0$ $\leftrightarrow$ $^3P_0$ transition in $^{115}$In$^+$. $^{172}$Yb$^+$ ions are co-trapped and used for sympathetic cooling. Reproducible interrogation conditions for mixed-species Coulomb crystals are ensured by a conditional preparation sequence with permutation control. We demonstrate clock operation with a 1In$^+$-3Yb$^+$ crystal, achieving a relative systematic uncertainty of $2.5\times10^{-18}$ and a relative frequency instability of $1.6\times10^{-15}/\sqrt{\tau/1\;s}$. We report on an absolute frequency measurement with an uncertainty of $1.3\times10^{-16}$ and optical frequency ratios relative to the $^{171}$Yb$^+$ (E3) and $^{87}$Sr clock transitions with fractional uncertainties of $4.4$ and $4.7$ parts in 10$^{18}$, respectively. The latter are among the most precise measurements of frequency ratios to date and improve upon the previous uncertainty of the $^{115}$In$^+$/$^{87}$Sr ratio by two orders of magnitude. We also demonstrate operation with four $^{115}$In$^+$ clock ions, which reduces the instability to $9.2\times10^{-16}/\sqrt{\tau/1\;s}$., Comment: 13 pages, 8 figures
- Published
- 2024