Project summary Publishable Summary (January 2021) Papers Intercontinental comparison of optical atomic clocks through very long baseline interferometry M. Pizzocaro, M. Sekido, K. Takefuji, H. Ujihara, H. Hachisu, N. Nemitz, M. Tsutsumi, T. Kondo, E. Kawai, R. Ichikawa, K. Namba, Y. Okamoto, R. Takahashi, J. Komuro, C. Clivati, F. Bregolin, P. Barbieri, A. Mura, E. Cantoni, G. Cerretto, F. Levi, G. Maccaferri, M. Roma, C. Bortolotti, M. Negusini, R. Ricci, G. Zacchiroli, J. Roda, J. Leute, G. Petit, F. Perini, D. Calonico and T. Ido Nature Physics (2020) – open access link will be provided after 6 month embargo period Improved limits for violations of local position invariance from atomic clock comparisons R. Lange, N. Huntemann, J. M. Rahn, C. Sanner, H. Shao, B. Lipphardt, C. Tamm, S. Weyers and E. Peik Physical Review Letters 126, 011102 (2021) Optical frequency ratio of a 171Yb+ single-ion clock and a 87Sr lattice clock S. Dörscher, N. Huntemann, R. Schwarz, R. Lange, E. Benkler, B. Lipphardt, U. Sterr, E. Peik and C. Lisdat Metrologia 58, 015005 (2021) Universal formalism for data sharing and processing in clock comparison networks J. Jodewyck, R. Le Targat, P.-E. Pottie, E. Benkler, S. Koke and J. Kronjäger Physical Review Research 2, 043269 (2020) Coherent suppression of tensor frequency shifts through magnetic field rotation R. Lange, N. Huntemann, C. Sanner, H. Shao, B. Lipphardt, C. Tamm and E. Peik Physical Review Letters 125, 143201 (2020) Associated dataset Long term measurement of the 87Sr clock frequency at the limit of primary Cs clocks R. Schwarz, S. Dörscher, A. Al-Masoudi, E. Benkler, T. Legero, U. Sterr, S. Weyers, J. Rahm, B. Lipphardt and C. Lisdat Physical Review Research 2, 033242 (2020) Associated dataset Coherent excitation of the highly forbidden electric octupole transition in 172Yb+ H. A. Fürst, C.-H. Yeh, D. Kalincev, A. P. Kulosa, L. S. Dreissen, R. Lange, E. Benkler, N. Huntemann, E. Peik and T. E. Mehlstäubler Physical Review Letters 125, 163001 (2020) Associated dataset Absolute frequency measurement of the 1S0 – 3P0 transition of 171Yb with a link to International Atomic Time M. Pizzocaro, F. Bregolin, P. Barbieri, B. Rauf, F. Levi and D. Calonico Metrologia 57, 035007 (2020) Associated dataset End-to-end topology for fiber comb based optical frequency transfer at the 10-21 level E. Benkler, B. Lipphardt, T. Puppe, R. Wilk, R. Rohde and U. Sterr Optics Express 27, 36886 – 36902 (2019) Associated dataset Talks Optical lattice clocks at NPL (seminar by William Bowden) http://empir.npl.co.uk/rocit/wp-content/uploads/sites/52/2020/07/Seminarium-Katedry-Fizyki-Atomowej-Molekularnej-i-Optycznej-20200619-1020-1.mp4 Funding statement: This project 18SIB05 ROCIT has received funding from the EMPIR programme co-financed by the Participating States and from the European Union’s Horizon 2020 research and innovation programme. Publicity resources – repository instructions and EURAMET logos.