Roadmap towards the redefinition of the second

Authors :: Dimarcq, N.
Gertsvolf, M.
Mileti, G.
Bize, S.
Oates, C. W.
Peik, E.
Calonico, D.
Ido, T.
Tavella, P.
Meynadier, F.
Petit, G.
Panfilo, G.
Bartholomew, J.
Defraigne, P.
Donley, E. A.
Hedekvist, P. O.
Sesia, I.
Wouters, M.
Dube, P.
Fang, F.
Levi, F.
Lodewyck, J.
Margolis, H. S.
Newell, D.
Slyusarev, S.
Weyers, S.
Uzan, J. -P.
Yasuda, M.
Yu, D. -H.
Rieck, C.
Schnatz, H.
Hanado, Y.
Fujieda, M.
Pottie, P. -E.
Hanssen, J.
Malimon, A.
Ashby, N.
Source :: Metrologia 61 012001 (2024)
Publication Year :: 2023
Abstract: This paper outlines the roadmap towards the redefinition of the second, which was recently updated by the CCTF Task Force created by the CCTF in 2020. The main achievements and the open challenges related to the status of the optical frequency standards, their contribution to time scales and UTC, the possibility of their comparison and the knowledge of the Earth's gravitational potential at the necessary level of uncertainty are discussed. In addition, the mandatory criteria to be achieved before redefinition and their current fulfilment level, together with the redefinition options based on a single or on a set of transitions are described.<br />Comment: 26 pages. This paper is based on the work of a CCTF Task Force on the roadmap to the redefinition of the second