Lutetium-ion clock sets a new accuracy record

Sep 23, 5:26 PM UTC

Two clocks reproduce their frequency to the 19th digit

Researchers reported two single-ion lutetium optical clocks agreeing to the 19th digit, the most precise clock comparison yet performed. Their system has an estimated uncertainty of 1 × 10^-19, about four times lower than the previous record holder. Lutetium is comparatively insensitive to temperature and magnetic-field changes, although comparisons with distant clocks remain difficult because millimetre-scale height differences affect measurements through gravity. The advance could support gravitational mapping and a future redefinition of the second; transportable versions remain a development goal.

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