Lu+ optical frequency references with accuracy verified at the 19th digit

Also Consider

Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context:

1. 1Validating a lutetium frequency reference2024
2. 2Clock with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mn>8</mml:mn><mml:mo>×</mml:mo><mml:msup><mml:mn>10</mml:mn><mml:mrow><mml:mo>−</mml:mo><mml:mn>19</mml:mn></mml:mrow></mml:msup></mml:math> Systematic Uncertainty2024 · 7 citations
3. 3A clock with $8\times10^{-19}$ systematic uncertainty2024 · 204 citations
4. 4$^{88}$Sr$^{+}$ optical clock with $7.9\times 10^{-19}$ systematic uncertainty and measurement of its absolute frequency with $9.8\times 10^{-17}$ uncertainty2025
5. 5¹⁷¹Yb⁺ optical clock with 2.2 × 10⁻¹⁸ systematic uncertainty and absolute frequency measurements2024 · 33 citations