Revision 2

Accepted · core change · record

Changes against revision 1:

Title: Can optical clocks meet the redefinition criteria by 2029?
Plain: Before the second is redefined, several optical clocks around the world must agree, be compared across continents and feed international time routinely. Whether that will be achieved in time for 2030 is not settled.
Precise · changed · core: Revision 1: Determine whether the mandatory criteria of the CCTF roadmap (Dimarcq et al 2024), including repeated agreement of independent optical clocks and frequency ratios at the low-1e-18 level, continuous contributions to TAI and intercontinental comparisons at that level, are met by 2029 for one species or for an ensemble defining a weighted geometric-mean frequency.; Revision 2: Determine whether the mandatory criteria of the CCTF roadmap (Dimarcq et al 2024), including repeated agreement of independent optical clocks and frequency ratios at the low-$10^{-18}$ level, continuous contributions to TAI and intercontinental comparisons at that level, are met by 2029 for one species or for an ensemble defining a weighted geometric-mean frequency.
Settled by: BIPM and CCTF assessment confirming each mandatory criterion with published comparison data.
Kind: well-posed
Answer type: yes-no
References: (empty)
Literature status: open
Status note: The 28th CGPM (2026) is to consider the choice of option and species; adoption is expected at the earliest at the 29th CGPM in 2030.
Posed since: (empty)

Decisions