News

NPL's and PTB's measurements of the 171Yb+ optical frequency standard have been published in Physics Review Letters.

Atomic clocks form the basis of timekeeping and are used in navigation and communications. The most advanced optical clocks now exceed the best clocks based on the current definition of the second in terms of reproducibility.

Joint Research Project SIB04 - High-accuracy optical clocks with trapped ions (short name: Ion Clock) aims to produce a selection of optical clocks and make improvements to key components within the clocks. The goal of the project is to comprehensively evaluate the performance of these optical clocks as well as to provide sets of frequency measurements, with the potential to become primary standards and used as input to a redefinition of the second. The measurements of the optical frequency standard have allowed the project to place new limits on potential time variation of fundamental constants.

As well as being published in Physical Review Letters, the American Physical Society selected these papers, not only as an Editor's Suggestion but also to feature in their highlights journal Physics - spotlighting exceptional research.

More information on the EMRP project SIB04 Ion clock is available on the EURAMET project page >>