Frequency Comparison of [Formula see text] Ion Optical Clocks at PTB and NPL via GPS PPP

Frequency Comparison of [Formula : see text] Ion Optical Clocks at PTB and NPL via GPS PPP

We used precise point positioning, a well-established GPS carrier-phase frequency transfer method to perform a direct remote comparison of two optical frequency standards based on single laser-cooled [Formula: see text] ions operated at the National Physical Laboratory (NPL), U.K. and the Physikalis...

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Veröffentlicht in:IEEE transactions on ultrasonics, ferroelectrics, and frequency control. - 1986. - 63(2016), 7 vom: 21. Juli, Seite 981-5
1. Verfasser: Leute, J (VerfasserIn)
Weitere Verfasser: Huntemann, N, Lipphardt, B, Tamm, Christian, Nisbet-Jones, P B R, King, S A, Godun, R M, Jones, J M, Margolis, H S, Whibberley, P B, Wallin, A, Merimaa, M, Gill, P, Peik, E
Format: Online-Aufsatz
Sprache:English
Veröffentlicht: 2016
Zugriff auf das übergeordnete Werk:IEEE transactions on ultrasonics, ferroelectrics, and frequency control
Schlagworte:Journal Article
Beschreibung
Zusammenfassung:We used precise point positioning, a well-established GPS carrier-phase frequency transfer method to perform a direct remote comparison of two optical frequency standards based on single laser-cooled [Formula: see text] ions operated at the National Physical Laboratory (NPL), U.K. and the Physikalisch-Technische Bundesanstalt (PTB), Germany. At both institutes, an active hydrogen maser serves as a flywheel oscillator which is connected to a GPS receiver as an external frequency reference and compared simultaneously to a realization of the unperturbed frequency of the (2)S1/2(F=0)-(2)D3/2(F=2) electric quadrupole transition in [Formula: see text] via an optical femtosecond frequency comb. To profit from long coherent GPS-link measurements, we extrapolate the fractional frequency difference over the various data gaps in the optical clock to maser comparisons which introduces maser noise to the frequency comparison but improves the uncertainty from the GPS-link instability. We determined the total statistical uncertainty consisting of the GPS-link uncertainty and the extrapolation uncertainties for several extrapolation schemes. Using the extrapolation scheme with the smallest combined uncertainty, we find a fractional frequency difference [Formula: see text] of -1.3×10(-15) with a combined uncertainty of 1.2×10(-15) for a total measurement time of 67 h. This result is consistent with an agreement of the frequencies realized by both optical clocks and with recent absolute frequency measurements against caesium fountain clocks within the corresponding uncertainties
Beschreibung:Date Completed 13.06.2017
Date Revised 13.06.2017
published: Print-Electronic
Citation Status PubMed-not-MEDLINE
ISSN:1525-8955
DOI:10.1109/TUFFC.2016.2524988