Researchers at the National University of Singapore's Centre for Quantum Technologies have developed a lutetium-based atomic clock. The device achieves an uncertainty of 1 x 10⁻¹⁹, which is the lowest reported for any optical atomic clock to date. The system uses a single lutetium-176 ion as a time reference and operates with a laser wavelength of 848 nanometers.
The lutetium clock is notable for its resistance to temperature fluctuations and magnetic fields, allowing for stable operation across diverse environments. To validate the performance, the team built two such clocks and compared them over 200 hours. The comparison achieved an uncertainty of 5.7 x 10⁻¹⁹, setting a new record for clock-to-clock stability measurements.
Due to its extreme sensitivity to gravity, the clock can detect time dilation caused by height differences of just 5 millimeters. During the experiment, researchers maintained the relative height of the two ions within a 1-millimeter margin to ensure accurate results. This sensitivity currently complicates comparisons with other global atomic clocks due to variations in Earth's gravitational field.
Optical atomic clocks offer higher precision than traditional cesium-based standards by utilizing higher-frequency atomic transitions. International standards bodies are currently evaluating these technologies to potentially redefine the second, with a target date of 2030 or later. The team is now working on miniaturizing the laboratory setup into a portable prototype for future field applications.
