Towards the optical second: verifying optical clocks at the SI limit.

ABSTRACT: The pursuit of ever more precise measures of time and frequency motivates redefinition of the second in terms of an optical atomic transition. To ensure continuity with the current definition, based on the microwave hyperfine transition in ¹³³Cs, it is necessary to measure the absolute frequency of candidate optical standards relative to primary cesium references. Armed with independent measurements, a stringent test of optical clocks can be made by comparing ratios of absolute frequency measurements against optical frequency ratios measured via direct optical comparison. Here we measure the S01→P03 transition of ¹⁷¹Yb using satellite time and frequency transfer to compare the clock frequency to an international collection of national primary and secondary frequency s

SUBMITTER: McGrew WF 

PROVIDER: S-EPMC11577666 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature