Common use of Key results and conclusions Clause in Contracts

Key results and conclusions. The objective of investigating the international consistency of optical clocks through a coordinated programme of frequency comparisons was therefore met, with the newly extended European optical fibre network having been shown to be capable of supporting comparisons with long-term fractional instability and accuracy below 10−18. The comparison campaign carried out in March 2022 was the most extensive ever performed, involving eleven optical clocks in seven different countries. Measurements of local optical frequency ratios included several that had never before been determined directly, and comparison uncertainties for the most advanced optical clocks were reduced by an order of magnitude or more compared to the state-of-the-art at the start of the project.