English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The frequency ratio of the 1S0(F=1/2)-3P0(F=1/2) clock transition in 171Yband the 1S0(F=9/2)-3P0(F=9/2) clock transition in 87Sr is measured by anoptical-optical direct frequency link between two optical lattice clocks. Wedetermined the ratio (\nu_{Yb}/\nu_{Sr}) to be 1.207 507 039 343 340 4(18) witha fractional uncertainty of 1.5x10^{-15}. The measurement uncertainty of thefrequency ratio is smaller than that obtained from absolute frequencymeasurements using the International Atomic Time (TAI) link. The measured ratioagrees well with that derived from the absolute frequency measurement resultsobtained at NIST and JILA, Boulder, CO using their Cs-fountain clock. Ourmeasurement enables the first international comparison of the frequency ratiosof optical clocks, and we obtained a good agreement between the two measuredratios with an uncertainty smaller than the TAI link. The measured frequencyratio will be reported to the International Committee for Weights and Measuresfor a discussion related to the redefinition of the second.

Frequency ratio measurement of 171Yb and 87Sr optical lattice clocks