Coordinated international comparisons between optical clocks connected via fiber and satellite links
thomas lindvall, Marco Pizzocaro, rachel godun, Michel Abgrall, Daisuke Akamatsu, Anne Amy-Klein, Erik Benkler, Nishant Bhatt, Davide Calonico, Étienne Cantin, E. Cantoni, Giancarlo Cerretto, Christian Chardonnet, Manuel Antonio Fernández-Villacañas Marín, Cecilia Clivati, Stefano Condio, E. Anne Curtis, Heiner Denker, Simone Donadello, Sören Dörscher, Chen-Hao Feng, Melina Filzinger, Thomas Fordell, Irene Goti, Kalle Hanhijärvi, H. N. Hausser, Ian R. Hill, Kazumoto Hosaka, Nils Huntemann, Matthew Johnson, Jonas Keller, Joshua Klose, Takumi Kobayashi, Sebastian Koke, Alexander Kühl, Rodolphe Le Targat, Thomas Legero, Filippo Levi, B. Lipphardt, Christian Lisdat, Hongli Liu, Jérôme Lodewyck, Olivier Lopez, Maxime Mazouth-Laurol, Tanja Mehlstaeubler, Alberto Mura, Akiko Nishiyama, T. Nordmann, Adam Parsons, Gérard Petit, Benjamin Pointard, Paul-Éric Pottie, Matias Risaro, Billy Robertson, M. Schioppo, Haosen Shang, Kilian Stahl, Martin Steinel, Uwe Sterr, Alexandra Tofful, Mads Tønnes, Dang Bao An Tran, Jacob Tunesi, Anders E. Wallin, H. S. Margolis
Abstract
Optical clocks provide ultraprecise frequency references that are vital for international metrology as well as for tests of fundamental physics. To investigate the level of agreement between different clocks, we simultaneously measured the frequency ratios between ten optical clocks in six different countries, using fiber and satellite links. This is the largest coordinated comparison to date, from which we present a subset of 38 optical frequency ratios and an evaluation of the correlations between them. Four ratios were measured directly for the first time to our knowledge, while others had significantly lower uncertainties than previously achieved, supporting the advance toward a redefinition of the second and the use of optical standards for international time scales.