European, Chinese Teams Build First Thorium-229 Nuclear Clock as Feedback Loop Clears Final Hurdle
Updated
Updated · Gizmodo · Jun 12
European, Chinese Teams Build First Thorium-229 Nuclear Clock as Feedback Loop Clears Final Hurdle
3 articles · Updated · Gizmodo · Jun 12
Summary
Two independent teams in Europe and China reported the first results from thorium-229 nuclear clocks built in calcium fluoride crystals, marking the first demonstrations of a working solid-state nuclear clock.
A feedback loop that stabilizes the clock’s operation supplied the key missing step, turning earlier thorium experiments into an actual clock rather than a proof of principle.
Thorium-229 is central because its nucleus can be driven between two states with lasers, while nuclei are about 10,000 times smaller than atoms and less vulnerable to temperature and electric-field noise.
The European team already used its device against leading atomic clocks in dark-matter searches and said it outperformed atomic clocks in some measurements, though both papers remain preprints and the technology is still early-stage.
Researchers see compact nuclear clocks as a route to sharper navigation and communications tools, as well as precision tests of fundamental physics and ultralight dark matter.
How will the race between European and Chinese teams to perfect the nuclear clock reshape global standards for time itself?
Beyond scientific discovery, how will a clock accurate for billions of years concretely impact our daily technology and infrastructure?
How can a device designed for perfect timekeeping effectively become a sensor to detect invisible particles like dark matter?
Thorium-229 Nuclear Clocks: Ushering in 10⁻¹⁹ Precision and a New Era of Timekeeping and Fundamental Physics
Overview
In 2024-2025, scientists achieved a major breakthrough by building the first working nuclear clock, marking the dawn of nuclear timekeeping. This advance was made possible by the unique properties of thorium-229, whose atomic nucleus has an exceptionally low-energy transition, making it ideal for precise time measurement. Years of dedicated research led to the successful direct laser excitation of this nuclear transition and the development of a sophisticated feedback mechanism to lock the laser frequency. These achievements promise to redefine our understanding of time and the universe, opening new frontiers in both technology and fundamental physics.