High-accuracy ion-based optical clocks

Project: EU project

Project Details


Future primary standards of time and frequency

Currently, the smallest systematic uncertainty is achieved by for single ion clocks. While the single ion can provide highest accuracy, it requires weeks of averaging to reach statistical uncertainty below 10–18. Much faster averaging is expected when employing more ions and reference transitions with higher frequencies.

will develop ion-based optical clocks with highest accuracy using multiple ions or transitions with higher frequencies and their performance will be demonstrated by intercomparisons.

will reduce the instability and uncertainty of its 88Sr+ clock by improving the ion trap with respect to the trap heating and by implementing an active stabilization of the magnetic field at the trap
as well as evaluate frequency shifts of multi-ion optical clocks.

Call 2023: Fundamental Metrology

The project (23FUN03 HIOC) has received funding from the European Partnership on Metrology, co-financed from the European Union’s Horizon Europe Research and Innovation Programme and by the Participating States.
Effective start/end date1/05/2430/04/27

Collaborative partners

  • VTT Technical Research Centre of Finland
  • German National Metrology Institute (PTB) (lead)
  • Bundesamt für Eich- und Vermessungswesen (BEV) (Project partner)
  • National Metrological Institute (INRIM) (Project partner)
  • Czech Metrology Institute (CMI) (Project partner)
  • Institute of Scientific Instruments of the CAS, v.v.i. (ISI) (Project partner)
  • Leibniz University Hannover (Project partner)
  • Max Planck Society (Project partner)
  • Vienna University of Technology (TU Wien) (Project partner)

Funding category

  • Horizon Europe


  • Optical clocks
  • single trapped ions
  • cooled ions
  • frequency standards
  • frequency comparisons
  • SI second