Scientists from the National University of Singapore have achieved a breakthrough in quantum measurements by creating a new type of ultra-precise atomic clock. Instead of elements traditionally used in such devices, such as cesium or rubidium, physicists have for the first time utilized atoms of lutetium, a rare heavy metal. Due to its large mass, lutetium significantly reduces measurement errors, enabling unprecedented timekeeping accuracy and taking optical standards to a fundamentally new level.
Advantages of the Heavy Element and Physical Principles
Lutetium has an atomic mass of 71 and is located at the end of the lanthanide series, right after ytterbium. As a metal extremely rare in nature, it possesses a unique set of properties. Because of the atom's large mass, its intrinsic oscillations are significantly smaller than those of cesium. Furthermore, the optical transition frequency in the lutetium clock reaches approximately 354 THz, which is about 10,000 times higher than the microwave transition frequency in classic cesium analogs. The combination of high frequency and minimal error makes the Singaporean physicists' development an accuracy leader.
Environmental Stability and Experimental Conditions
An important feature of heavy lutetium atoms is their reduced sensitivity to magnetic field fluctuations and temperature changes. This means that atomic clocks based on them will maintain equal stability both in temperate-latitude laboratories and in extreme conditions such as the North Pole or the Sahara Desert. During the experiment, researchers used a single ion of the lutetium-176 isotope, held in an electromagnetic trap at room temperature. A special laser with a wavelength of about 848 nm transferred the ion between two energy states, creating a stable time standard.
Record Performance and Application Prospects
A comparison of two independent setups over nearly 200 hours showed their frequencies matched with a relative discrepancy of about 10-19. The achieved systematic uncertainty was 1.2 and 1.3 × 10-19 for both systems, which is roughly four times better than the previous record for calcium-ion optical clocks set by Chinese specialists. Such precision allows for detecting gravitational potential changes at the millimeter height scale. In the future, the technology will find applications in ultra-precise geodesy, testing general relativity, and fundamental physical research.
Controversial Data
While most specialized sources agree on the relative frequency discrepancy level of 10-19 and the fourfold superiority over calcium clocks, public reports diverge regarding specific formulations of equivalent error in familiar time intervals. Some publications emphasize the theoretical stability of "one second of error over billions of years," whereas the researchers' technical reports operate with strict systematic uncertainty values in the range of 1.2–1.3 × 10-19 obtained during 200 hours of continuous testing of the setups at room temperature.
