Singapore researchers build highly precise atomic clock
Two lutetium clocks compared to the nineteenth decimal place in peer-reviewed Nature study.
Researchers at the National University of Singapore have developed an optical atomic clock with a reported uncertainty of approximately one part in 10^19. The results appeared in Nature on 23 September and set a record for this type of clock.
The clock uses a singly charged lutetium atom as a frequency reference. A laser is tuned to a transition between energy levels in the atom. The light frequency then serves as an extremely stable measure of time.
The researchers built two similar clocks and compared their ticks directly. The measured relative discrepancy was around 5.7 × 10^-19. According to the study, the uncertainty of the individual frequency references is approximately 1 × 10^-19.
That comparison is important because a clock must not only appear theoretically accurate, but also be reproducible. The Nature publication describes an extensive analysis of known systematic effects and a comparison lasting approximately two hundred hours. The study is peer-reviewed; an independent replication by another research group is not yet available.
According to the researchers, lutetium offers a practical advantage: the relevant atomic transition is relatively insensitive to changes in temperature and magnetic fields. This means the clock can operate at room temperature. That does not mean the technology is already ready for everyday use; the setup is still in a laboratory and requires complex lasers, vacuum equipment and measurement electronics.
More accurate clocks can be used for satellite navigation, communications networks and measurements of differences in gravity. Because time runs slightly more slowly at greater altitude, such clocks can also be used to study changes in the Earth's surface. The researchers also mention tests of fundamental physical theories and searches for dark matter.
A new definition of the second is not immediately in prospect. International metrology organisations are examining various optical clock technologies and must first reach agreement on comparability, reliability and practical applicability. The Singapore study is therefore an important measurement achievement, but not evidence that the current time standard is already being replaced.
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The technical results, uncertainty margins and publication status were directly checked in Nature and the institutional explanation. Future applications and a possible redefinition of the second are described as expectations and ongoing processes.
- confirmed The results appeared in Nature on 23 September 2026. — The Nature publication gives the publication date and DOI. source
- confirmed The clock uses lutetium and has a reported uncertainty of around 1 × 10^-19. — This is stated in the abstract of the peer-reviewed study. source
- confirmed Two clocks were compared directly, with a discrepancy of around 5.7 × 10^-19. — The study and NUS explanation report this comparison. source
- incorrect The study proves that the second will soon be revised. — The study contributes to ongoing discussions, but does not establish any decision on a new second. source
1 correction(s) applied
- Was: The new clock will redefine the second.Now: The results could contribute to a future redefinition of the second, but no decision has yet been taken. (The study describes a contribution to international metrology, not an established decision.)
Editor's note
The research is peer-reviewed and the measurements are described in the study. Independent replication and practical use outside the laboratory are still lacking.Sources
- Lu+ optical frequency references with accuracy verified at the 19th digit — Nature
- Singapore scientists build world’s most accurate atomic clock — Centre for Quantum Technologies, National University of Singapore
- Best clock ever: timekeeper based on lutetium atoms wows researchers — Nature News
More on this in Dutch media
- NU.nl — „atoomklok lutetium”
- De Telegraaf — „atoomklok lutetium”
- AD — „atoomklok lutetium”