From Nature · · 1m
Thorium Nuclear Clock Breakthrough
Scientists create first optical nuclear clock using thorium-229, achieving unprecedented stability for dark matter detection.
In brief
Scientists create first optical nuclear clock using thorium-229, achieving unprecedented stability for dark matter detection. Researchers built a thorium-229 nuclear clock with 10^-15 stability over a day, using it to constrain ultralight dark matter models. Originally reported by Nature.
Thorium-229 Nuclear Clock Realized
Scientists created the first optical nuclear clock using thorium-229, stabilizing a laser to its 148-nm nuclear transition.
Room-Temperature Crystal Setup
Thorium-229 nuclei are embedded in a millimetre-sized, room-temperature calcium fluoride crystal for stability.
Subharmonic Laser Comparison
A subharmonic of the 148-nm radiation is continuously compared with a Yb+ single-ion clock for precision.
Shot-Noise Limited Stability
The clock shows a shot-noise-limited fractional frequency instability of 3×10^-12/√(τ/s) over 1 day of operation.
Dark Matter Detection
Researchers used the clock to search for periodic fluctuations in the nuclear transition energy between 20 seconds and 1 day.
Enhanced Dark Matter Constraints
The clock's sensitivity improves dark matter coupling measurements beyond previous atomic clock results.
The key point
Researchers built a thorium-229 nuclear clock with 10^-15 stability over a day, using it to constrain ultralight dark matter models.
