... that I came across recently and would like to share: 1. "Towards the optical second: verifying optical clocks at the SI limit" by W. F. McGrew et al: https://doi.org/10.1364/OPTICA.6.000448 (open access) -- reports best absolute measurement of Yb-171 optical transition in a lattice clock with fractional uncertainity of 2×10^-16. (See also their supplementary material with absolute frequency comparisons of other best performing clocks).
2. "Optical clock intercomparison with 6×10^−19 precision in one hour" by E. Oelker et al.: https://arxiv.org/abs/1902.02741 -- sets frequency stability record of 4×10^-17/sqrt(tau) in Sr-87 lattice clock. Performance of their flywheel oscillator -- cryogenic silicon reference cavity 1542nm laser is truly awesome. 3. "An 27Al+ quantum-logic clock with systematic uncertainty below 10^-18" by S. M. Brewer et al.: https://arxiv.org/abs/1902.07694 -- compared to lattice clocks with thousands of atoms, a lone trapped Al-27+ ion quantum logic clock is limited by quantum projection noise 'only' to 10^-15/sqrt(tau), but instead achieves best systematic uncertainity below 10^-18 level. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
