CoChat
Sign Up
Cited by 83Advanced Frequency and Time StandardsNetwork Time Synchronization TechnologiesScientific Measurement and Uncertainty Evaluation

Months-long real-time generation of a time scale based on an optical clock

Open access
Hachisu, Hidekazu, Nakagawa, Fumimaru, Hanado, Yuko, Ido, Tetsuya·2018·Scientific Reports
DOI 10.1038/s41598-018-22423-5PMC PMC5844947
Open this paper in CoChat — free accountOpen PDF

Abstract

Time scales consistently provide precise time stamps and time intervals by combining atomic frequency standards with a reliable local oscillator. Optical frequency standards, however, have not been applied to the generation of time scales, although they provide superb accuracy and stability these days. Here, by steering an oscillator frequency based on the intermittent operation of a 87 Sr optical lattice clock, we realized an “optically steered” time scale TA(Sr) that was continuously generated for half a year. The resultant time scale was as stable as International Atomic Time (TAI) with its accuracy at the 10−16 level. We also compared the time scale with TT(BIPM16). TT(BIPM) is computed in deferred time each January based on a weighted average of the evaluations of the frequency of TAI using primary and secondary frequency standards. The variation of the time difference TA(Sr) – TT(BIPM16) was 0.79 ns after 5 months, suggesting the compatibility of using optical clocks for time scale generation. The steady signal also demonstrated the capability to evaluate one-month mean scale intervals of TAI over all six months with comparable uncertainties to those of primary frequency standards (PFSs).

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Integrity signals

Registry

Crossref · 10.1038/s41598-018-22423-5

Cites

6 of 6 references verified0 citation errors · 0 not checkable

Statistics

Claims the paper makes

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • They used the VLBI frequency link to compare two optical clocks: IT-Yb1 at INRIM in Torino and NICT-Sr1 in Koganei.

    “We used this VLBI frequency link to compare two optical clocks: the ytterbium-171 optical lattice clock 34 IT-Yb1 at INRIM in Torino (Italy) and the strontium-87 optical lattice clock 35,36 NICT-Sr1 in Koganei.”

    From Intercontinental comparison of optical atomic clocks through very long baseline interferometry (2021) · cites this paper as [36]

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

The self-check needs the paper’s full text.

Cites

Flagged first, then by citations

Research works printed but not linked: 26

  1. [2]Panfilo G Harmegnies A Tisserand L A new prediction algorithm for the generation of International Atomic Time Metrologia 2011 49 49 56 10.1088/0026-1394/49/1/008 · DOI
  2. [3]Panfilo G Harmegnies A Tisserand L A new weighting procedure for UTC Metrologia 2014 51 285 292 10.1088/0026-1394/51/3/285 · DOI
  3. [5]Bauch A Weyers S Piester D Staliuniene E Yang W Generation of UTC(PTB) as a fountain-clock based time scale Metrologia 2012 49 180 188 10.1088/0026-1394/49/3/180 · DOI
  4. [6]Rovera GD UTC(OP) based on LNE-SYRTE atomic fountain primary frequency standards Metrologia 2016 53 S81 S88 10.1088/0026-1394/53/3/S81 · DOI
  5. [7]Domnin YS The MTsR-F2 fountain-type cesium frequency standard Meas. Tech. 2013 55 1155 1162 10.1007/s11018-012-0102-0 · DOI
  6. [8]Peil S Hanssen J Swanson TB Taylor J Ekstrom CR The USNO rubidum fountains J. Phys. Conf. Ser. 2016 723 012004 10.1088/1742-6596/723/1/012004 · DOI
  7. [11]Ido T Hachisu H Nakagawa F Hanado Y Rapid evaluation of time scale using an optical clock J. Phys. Conf. Ser. 2016 723 012041 10.1088/1742-6596/723/1/012041 · DOI
  8. [13]Kumagai M Ito H Kajita M Hosokawa M Evaluation of caesium atomic fountain NICT-CsF1 Metrologia. 2008 45 139 148 10.1088/0026-1394/45/2/003 · DOI
  9. [14]Guéna, J. et al. Progress in atomic fountains at LNE-SYRTE. IEEE Trans. Ultrson. Ferroelect., Freq. Control.59, 391–410 (2012). 22481772
  10. [15]Lipphardt B Gerginov V Weyers S Optical Stabilization of a Microwave Oscillator for Fountain Clock Interrogation IEEE Trans. Ultrason. Ferroelect., Freq. Control. 2017 64 761 766 10.1109/TUFFC.2017.2649044 28103194 · DOI
  11. [17]Panfilo G Tavella P Atomic clock prediction based on stochastic differential equation Metrologia. 2008 45 S108 S116 10.1088/0026-1394/45/6/S16 · DOI
  12. [19]Hachisu H Petit G Nakagawa F Hanado Y Ido T SI-traceable measurement of an optical frequency at low 10−16 level without a local primary standard Opt. Express. 2017 25 8511 8523 10.1364/OE.25.008511 28437930 · DOI · Paper page
  13. [20]Hachisu H Petit G Ido T Absolute frequency measurement with uncertainty below 1 × 10−15 using International Atomic Time Appl. Phys. B. 2017 123 34 10.1007/s00340-016-6603-9 · DOI
  14. [21]Nakagawa F Imae M Hanado Y Aida M Development of Multichannel Dual-Mixer Time Difference System to Generate UTC(NICT) IEEE Trans. Instrum. Meas. 2005 54 829 832 10.1109/TIM.2004.843382 · DOI · Paper page
  15. [22]Hanado Y The New Generation System of Japan Standard Time at NICT International Journal of Navigation and Observation. 2008 2008 841672 10.1155/2008/841672 · DOI
  16. [24]Weyers S Gerginov V Nemitz N Li R Gibble K Distributed cavity phase frequency shifts of the caesium fountain PTB-CSF2 Metrologia. 2012 49 82 87 10.1088/0026-1394/49/1/012 · DOI
  17. [25]Yu D Weiss M Parker T Uncertainty of a frequency comparison with distributed dead time and measurement interval offset Metrologia. 2007 44 91 96 10.1088/0026-1394/44/1/014 · DOI · Paper page
  18. [26]Guéna J Abgrall M Clairon A Bize S Contributing to TAI with a secondary representation of the SI second Metrologia. 2014 51 108 120 10.1088/0026-1394/51/1/108 · DOI
  19. [27]Peil S Swanson TB Hanssen J Taylor J Microwave-clock timescale with instability on order of 10−17 Metrologia. 2017 54 247 252 10.1088/1681-7575/aa65f7 · DOI
  20. [28]Robert C Conan JM Wolf P Impact of turbulent phase noise on frequency transfer with asymmetric two-way ground-satellite coherent optical links J.Phys. Conf. Ser. 2016 723 012039 10.1088/1742-6596/723/1/012039 · DOI
  21. [29]Matei DG 1.5 μm lasers with sub-10 mHz linewidth Phys. Rev. Lett. 2017 118 263202 10.1103/PhysRevLett.118.263202 28707932 · DOI
  22. [31]Lodewyck J Optical to microwave clock frequency ratios with a nearly continuous stronitum optical lattice clock Metrologia. 2016 53 1123 1130 10.1088/0026-1394/53/4/1123 · DOI · Paper page
  23. [32]Azoubib J Granveaud M Guinot B Estimation of the Scale Unit Duration of Time Scales Metrologia. 1977 13 87 93 10.1088/0026-1394/13/3/001 · DOI
  24. [33]Allan D Time and frequency (time-domain) characterization, estimation, and prediction of precision clock and oscillators IEEE Trans. Ultrason, Ferroelect., Freq. Control. 1987 34 647 654 10.1109/T-UFFC.1987.26997 18291897 · DOI
  25. [34]Degenhardt C Calcium optical frequency standard with ultracold atoms: Approaching 10−15 relative uncertainty Phys. Rev. A. 2005 72 062111 10.1103/PhysRevA.72.062111 · DOI
  26. [35]Panfilo G Parker TE A theoretical and experimental analysis of frequency transfer uncertainty, including frequency transfer into TAI Metrologia. 2010 47 552 560 10.1088/0026-1394/47/5/005 · DOI

Cited by

Sorted by citations

Authors
Hachisu, H., Nakagawa, F., Hanado, Y., & Ido, T.
Affiliations
National Institute of Information and Communications Technology (JP)
Corresponding author
Ido, Tetsuya
ORCID
Venue
Scientific Reports
Publisher
Springer Science and Business Media LLC
Published
2018-03-09
Volume
8
Issue
1
Pages
4243-4243
ISSN
2045-2322 (ISSN-L)
DOI
10.1038/s41598-018-22423-5
PMC
PMC5844947
OpenAlex
W2962890181
Cited by
83
References
6
Citations by year
2026: 9 · 2025: 11 · 2024: 9 · 2023: 15 · 2022: 5 · 2021: 3 · 2020: 13 · 2019: 11 · 2018: 7
FWCI
3.93
Type
journal article
Language
en
Open access
Licence
Locations
  • Scientific Reports (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • arXiv (Cornell University) (submittedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion)
  • Figshare (submittedVersion, cc-by)
  • arXiv (Cornell University) (cc-by)
Topics
  • Physical Sciences › Physics and Astronomy › Atomic and Molecular Physics, and Optics › Advanced Frequency and Time Standards
  • Physical Sciences › Computer Science › Computer Networks and Communications › Network Time Synchronization Technologies
  • Social Sciences › Decision Sciences › Statistics, Probability and Uncertainty › Scientific Measurement and Uncertainty Evaluation
Keywords
time scales, optical lattice clock, strontium-87, optical frequency standard, temporal stability, International Atomic Time, frequency stability, primary frequency standard

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review