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Journal Articles Nature Physics Year : 2021

Intercontinental comparison of optical atomic clocks through very long baseline interferometry

Marco Pizzocaro
  • Function : Author
Mamoru Sekido
  • Function : Author
Kazuhiro Takefuji
  • Function : Author
Hideki Ujihara
  • Function : Author
Hidekazu Hachisu
  • Function : Author
Nils Nemitz
  • Function : Author
Masanori Tsutsumi
  • Function : Author
Tetsuro Kondo
  • Function : Author
Eiji Kawai
  • Function : Author
Ryuichi Ichikawa
  • Function : Author
Kunitaka Namba
  • Function : Author
Yoshihiro Okamoto
  • Function : Author
Rumi Takahashi
  • Function : Author
Junichi Komuro
  • Function : Author
Cecilia Clivati
  • Function : Author
Filippo Bregolin
  • Function : Author
Piero Barbieri
  • Function : Author
Alberto Mura
  • Function : Author
Elena Cantoni
  • Function : Author
Giancarlo Cerretto
  • Function : Author
Filippo Levi
  • Function : Author
Giuseppe Maccaferri
  • Function : Author
Mauro Roma
  • Function : Author
Claudio Bortolotti
  • Function : Author
Monia Negusini
  • Function : Author
Roberto Ricci
  • Function : Author
Giampaolo Zacchiroli
  • Function : Author
Juri Roda
  • Function : Author
Gérard Petit
  • Function : Author
Federico Perini
  • Function : Author
Davide Calonico
  • Function : Author
Tetsuya Ido
  • Function : Author

Abstract

The comparison of distant atomic clocks is foundational to international timekeeping, global positioning and tests of fundamental physics. Optical-fibre links allow the most precise optical clocks to be compared, without degradation, over intracontinental distances up to thousands of kilometres, but intercontinental comparisons remain limited by the performance of satellite transfer techniques. Here we show that very long baseline interferometry (VLBI), although originally developed for radio astronomy and geodesy, can overcome this limit and compare remote clocks through the observation of extragalactic radio sources. We developed dedicated transportable VLBI stations that use broadband detection and demonstrate the comparison of two optical clocks located in Italy and Japan separated by 9,000 km. This system demonstrates performance beyond satellite techniques and can pave the way for future long-term stable international clock comparisons.

Dates and versions

insu-03713043 , version 1 (04-07-2022)

Identifiers

Cite

Marco Pizzocaro, Mamoru Sekido, Kazuhiro Takefuji, Hideki Ujihara, Hidekazu Hachisu, et al.. Intercontinental comparison of optical atomic clocks through very long baseline interferometry. Nature Physics, 2021, 17, pp.223-227. ⟨10.1038/s41567-020-01038-6⟩. ⟨insu-03713043⟩
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