The ROCIT consortium will be hosting a 2-day online workshop on 19th and 20th October 2022. The workshop will focus on the findings and results of our project, which has been working towards many of the milestones in the international roadmap towards a redefinition of the SI second. Topics covered will include improvements to the… Read More

The latest update to the Recommended values of standard frequencies, published by the  CCL-CCTF Frequency Standards Working Group (CCL-CCTF-WGFS) was strongly influenced by ROCIT activities. The new values were used for the first time for the calculation of International Atomic Time (TAI) in the April 2022 edition of Circular T (no. 412), allowing optical clocks… Read More

For the first time, five optical clocks appeared in the March 2022 edition of the Circular T (no. 411), contributing to the steering of International Atomic Time (TAI). These were the Yb clocks of KRISS, NMIJ and INRIM and the Sr clocks of  NICT and SYRTE. The clocks of SYRTE, INRIM and collaborator NMIJ operated… Read More

In an experiment performed in collaboration with members of the TiFOON consortium, we have set a new record for comparison of distant ultrastable lasers through an optical fibre network.  Our work, published today in Nature Communications, demonstrates how the precision of cutting-edge optical frequency standards in national metrology institutes can be made available through optical… Read More

Software developed within the ROCIT project for real-time evaluation of the blackbody radiation shift has been published as open source on GitHub. The blackbody radiation shift affects atomic clocks and it depends on the ambient temperature seen by the atoms. This software reads the ambient temperature from a multimeter and outputs a plot of the… Read More

Data from the strontium optical lattice clock SYRTE-Sr2 has been included in 3 editions of Circular T (June, July, August) and used for TAI steering. This data had high uptime, and was also submitted with low latency (before the 4th day of the following month), increasing the weight that it could have in the computation.… Read More

The ROCIT consortium held our M30 progress meeting on 18th & 19th October 2021. Despite having to be held virtually, it was a productive meeting including technical discussions on the work carried out and next steps, in particular plans for the international optical clock comparison planned for February / March 2022. The meeting also included… Read More

Tools developed within the ROCIT project for remote laser stabilisation and monitoring have been published on the open source GitHub project.  These include components for monitoring laser wavelengths and for locking lasers to a commerical wavemeter.… Read More

Our collaborators in the TiFOON project are hosting a free two-day workshop Time and Frequency Dissemination over Optical Fibre Networks, examining state of the art and future developments and applications in dissemination of time and frequency over optical fibre networks. More details are available on their website.… Read More

Comparisons of two optical clocks based on the E2 and E3 optical clock transitions in 171Yb+ at PTB have been analysed for potential violations of local position invariance. The limits for fractional temporal variations of the fine structure constant and the proton-to-electron mass ratio have been improved by factors of about 20 and 2 respectively.… Read More