Long-term measurements of the 87Sr optical clock frequency at PTB have provided an improved limit on the coupling of the gravitational potential of the Sun to the proton-to-electron mass ratio μ. The analysis, performed on a series of 42 measurements of the transition frequency over three years from 2017 to 2019, is published in Physical… Read More


ROCIT researcher Anne Curtis from NPL was recently interviewed by science writer Rachel Nuwer for an article on the redefinition of the SI second. The final article, entitled “Inside the incredibly slow race to reinvent time” was published as the cover story in the 19th August edition of New Scientist. and mentions the efforts underway… Read More


William Bowden from NPL recently gave a virtual talk at UMK. Entitled “Strontium optical lattice clocks at NPL”, this covered a recent measurement of the absolute frequency of the Sr clock transition as well as the work being carried out within the ROCIT project to improve the reliability of the system. William also presented recent… Read More


Our second formal collaboration agreement is with the consortium for the EMPIR-funded TiFOON project. The overall objective of that project is to advance fibre-based frequency transfer capabilities in Europe towards a sustainable, universal tool for time and frequency metrology, matching the unprecedented accuracy of modern optical clocks. Of particular interest to the ROCIT consortium is… Read More


We have signed a Letter of Agreement with AIST, NMIJ, who join the ROCIT project as our first collaborator. AIST will collaborate on methods for improving the robustness and automation of optical lattice clocks, as well as joining our international clock comparison campaigns using via GPS-based satellite links.… Read More


The M9 meeting for the ROCIT consortium was hosted by INRIM on February 19th – 20th 2020. This was a great opportunity to catch up with colleagues and discuss progress, as well as to finalise plans for the international optical clock comparison campaign planned for March.… Read More


A new optical fibre link has been set up from Paris to Turin to extend the reach of the European optical clock network. The full characterisation of this link is still in progress, but once optimised this will enable optical clocks in four different European laboratories to be compared at a level commensurate with the… Read More


INRIM have submitted data from their Yb optical lattice clock, collected prior to the start of the ROCIT project, to the BIPM. Following approval from the CCTF Working Group on Primary and Secondary Frequency Standards, this data appeared in Circular T no. 383 (November 2019) and was used for TAI steering.… Read More


ROCIT partner UMK is pleased to announce the upcoming Autumn School on “Clocks, Cavities, and Fundamental Physics”, which will take place at the Institute of Physics, Nicolaus Copernicus University in Torun, Poland, from 15th – 20th September 2019. The school welcomes students and postdocs from all over the world, and will focus on experiments and… Read More


On 5th – 6th June 2019, NPL welcomed representatives from all but one of the partner organisations to the ROCIT kick-off meeting. Based on the productive discussions that took place over the course of the two-day meeting, we are looking forward to a fruitful collaboration!  … Read More