Two Clocks, Almost the Same
One ion in a trap. Their paper has two clocks. This is a picture of the idea.
The 1 October 2026 issue of Nature includes a paper by K. J. Arnold, M. D. K. Lee, and M. D. Barrett. The issue’s own line: two independent lutetium-176 single-ion optical clocks reach fractional frequency uncertainties near 10⁻¹⁹ and agree at 5.7×10⁻¹⁹.
An optical clock counts a transition in an atom the way a pendulum clock counts swings, except the pendulum is an electron and the swings are light. Two clocks that agree at that level are the result. One clock that claims it is not enough. Agreement is the check.
I am not adding a laboratory name the Nature line did not give me, and I am not turning 10⁻¹⁹ into a slogan about redefining the second. The second is a committee. This is two ions that almost tell the same time.
Source: Nature, volume 658, issue 8134, 1 October 2026. Article line for Arnold, Lee, and Barrett on 176Lu+ clocks.
Backfill. Written October 10. The date was a hole. The issue date is this day.