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Optical clocks for the redefinition of the SI second

    Project: EU project

    Project Details

    Description

    Bringing European optical clocks to the stage where they regularly contribute to International Atomic Time.

    A future redefinition of the second is anticipated as optical atomic clocks have overtaken caesium clocks in terms of fractional frequency instability and estimated systematic uncertainty. However, no optical clock has yet contributed to the TAI.

    Project brings optical clocks to the point where they can contribute regularly to the international timescales. This is a prerequisite for redefinition of the second in terms of an optical frequency.

    VTT MIKES develops a Sr+ optical clock and contributes to clock comparisons via GPS PPP links.


    Call 2018: SI Broader Scope

    This project has received funding from the EMPIR programme co-financed by the Participating States and from the European Union’s Horizon 2020 research and innovation programme.
    AcronymROCIT
    StatusFinished
    Effective start/end date1/05/19 → 30/04/22

    Collaborative partners

    • National Physics Laboratory (NPL) (lead)
    • Czech Metrology Institute (CMI) (Project partner)
    • Central Office of Measures (GUM) (Project partner)
    • National Metrological Institute (INRIM) (Project partner)
    • Laboratoire National de Métrologie et d’Essais (LNE) (Project partner)
    • Paris Observatory (Project partner)
    • German National Metrology Institute (PTB) (Project partner)
    • Ben-Gurion University of the Negev (Project partner)
    • French National Center for Scientific Research (CNRS) (Project partner)
    • Leibniz University Hannover (Project partner)
    • Politecnico di Torino (Project partner)
    • Space Research Center of the Polish Academy of Sciences (Project partner)
    • Nicolaus Copernicus University (Project partner)

    Funding

    • EURAMET e.V.

    UN Sustainable Development Goals

    In 2015, UN member states agreed to 17 global Sustainable Development Goals (SDGs) to end poverty, protect the planet and ensure prosperity for all. This project contributes towards the following SDG(s):

    1. SDG 9 - Industry, Innovation, and Infrastructure
      SDG 9 Industry, Innovation, and Infrastructure

    Keywords

    • optical clock
    • atomic clock
    • SI second
    • international timescales

    Access Project

    • 2 Article
    • 1 Report
    • 1 Article in a proceedings journal

    • 88Sr+ optical clock with 7.9×10−19 systematic uncertainty and measurement of its absolute frequency with 9.8×10−17 uncertainty

      Lindvall, T., Fordell, T., Hanhijärvi, K. J., Doležal, M., Rahm, J., Weyers, S. & Wallin, A. E., 27 Oct 2025, In: Physical Review Applied. 24, 044082.

      Research output: Contribution to journal › Article › Scientific › peer-review

      Open Access
      5   Link opens in a new tab Citations (Scopus)

    • 18SIB05 ROCIT – Robust Optical Clocks for International Timescales: Final

      Lindvall, T. & ROCIT project, 2024, Euramet. 23 p. (VTT Research Report; No. VTT-R-00148-24).

      Research output: Book/Report › Report

      Open Access
      File
      272 Downloads (Pure)

    • Robust Optical Clocks for International Timescales (ROCIT)

      Margolis, H. S., Godun, R. M., Huntemann, N., Le Targat, R., Pizzocaro, M., Zawada, M., Abgrall, M., Akamatsu, D., Álvarez Martínez, H., Amy-Klein, A., Andia, M., Benkler, E., Bhatt, N. M., Bilicki, S., Bize, S., Bober, M., Calonico, D., Cambier, V., Cantin, E. & Chardonnet, C. & 73 others, Cifuentes Marín, M., Clivati, C., Condio, S., Curtis, E. A., Czubla, A., Doležal, M., Dörscher, S., Dunst, P., Feng, C.-H., Filzinger, M., Folman, R., Fordell, T., Formichella, V., Foucault, Y., Galleani, L., Goti, I., Groswasser, D., Gruszczyński, M., Guo, C., Hanhijärvi, K., Hausser, H. N., Hill, I. R., Hosaka, K., Johnson, M. Y. H., Keller, J., Klose, J., Kobayashi, T., Koke, S., Kovačić, D., Křen, P., Kuhl, A., Ledziński, A., Lemański, D., Levi, F., Lindvall, T., Lisdat, C., Liu, H., Lodewyck, J., Lopez, O., Lorini, L., Lours, M., Mašika, P., Mazouth-Laurol, M., Mehlstaubler, T. E., Moreno, W., Morzyński, P., Narożnik, M., Nawrocki, J., Nishiyama, A., Nogaś, P., Nordmann, T., Parsons, A. O., Pointard, B., Pottie, P. E., Risaro, M., Robertson, B. I., Romero González, J., Schioppo, M., Sesia, I., Shang, H., Signorile, G., Stahl, K., Steinel, M., Sterr, U., Suárez Ramírez, J., Tofful, A., Tønnes, M., Tran, A., Tunesi, J., Wallin, A., Waterholter, T., Zarei, M. & Zyskind, C., Nov 2024, In: Journal of Physics: Conference Series. 2889, 012022.

      Research output: Contribution to journal › Article in a proceedings journal › Scientific › peer-review

      Open Access
      4   Link opens in a new tab Citations (Scopus)
    View all 4 research outputs