Physicists have taken a significant stride toward creating the most precise atomic clock ever, with an accuracy of one second in 300 billion years, through the development of a pulse generator based on scandium at the European X-Ray Free-Electron Laser (XFEL) facility. This achievement represents a major milestone in the quest for a new generation of atomic clocks that promise a thousandfold increase in timekeeping precision.
Currently, atomic clocks are the world’s most accurate timekeepers, defining time through energy transitions of electrons in atomic shells of elements like cesium or strontium. These clocks are accurate to within one second over 300 million years (cesium atomic clock) and 15 billion years (experimental strontium atomic clock). Researchers have been working on nuclear clocks, which rely on transitions involving atomic nuclei instead of electrons, aiming to achieve greater accuracy.
At the European XFEL facility, an international team led by Argonne National Laboratory senior physicist Yuri Shvyd’ko successfully irradiated a thin piece of high-purity scandium foil with X-rays generated by the European XFEL. They observed the characteristic fluorescence that signaled scandium nucleus resonance, demonstrating a resonance of 1.4 quadrillionths of an electron volt. This result implies a potential accuracy of 1:10,000,000,000,000, equivalent to one second in 300 billion years.