5 papers
Optical clocks with accuracy validated at the 19th digit
K. J. Arnold, M. D. K. Lee, Zhao Qi +4
We report a comprehensive evaluation of all known sources of systematic uncertainty for two independent Lu single-ion optical references, finding total systematic uncer…
Precision measurement of the microwave clock transitions
M. D. K. Lee, Qi Zhao, Qin Qichen +4
We report precision measurement of the unperturbed microwave transition frequencies in to a fractional uncertainty of . We find t…
Zeeman Degenerate Sideband Cooling in Lu
Qin Qichen, Qi Zhao, M. D. K. Lee +4
We explore degenerate Raman sideband cooling in which neighboring Zeeman states of a fixed hyperfine level are coupled via a two-photon Raman transition. The degenerate coupling be…
Absolute frequency measurement of a Lu optical frequency standard via link to international atomic time
Zhao Zhang, Qi Zhao, Qin Qichen +4
We report on an absolute frequency measurement of the standard frequency which is defined as the hyperfine-average of to o…
An extrapolation method for polarizability assessments of ion-based optical clocks
K. J. Arnold, M. D. Barrett
We present a numerical method for extrapolating polarizability measurements to dc as done in the assessment of blackbody radiation shifts for ion-based clocks. The method explicitl…