paper

Optical frequency ratio of a single-ion clock and a lattice clock

arXiv:2009.05470 · doi:10.1088/1681-7575/abc86f

Abstract

We report direct measurements of the frequency ratio of the 642 THz -- electric octupole transition in and the 429 THz -- transition in . A series of 107 measurements has been performed at the Physikalisch-Technische Bundesanstalt between December 2012 and October 2019. Long-term variations of the ratio are larger than expected from the individual measurement uncertainties of few . The cause of these variations remains unknown. Even taking these into account, we find a fractional uncertainty of the frequency ratio of , which improves upon previous knowledge by one order of magnitude. The average frequency ratio is . This represents one of the most accurate measurements between two different atomic species to date.

9 pages, 4 figures, 1 table

References in corpus (15)

Cited by in corpus (13)