A chip-scale nuclear clock could be a hundred times more precise than the atomic clocks used to run GPS today.
April 23, 2026
Original Paper
Toward nanophotonic platforms for solid-state 229Th nuclear clocks
arXiv · 2604.20687
The Takeaway
Modern timekeeping relies on the vibrations of electrons, which are sensitive to external interference. This new prototype uses the nucleus of Thorium-229, which is much better shielded from the environment and vibrates at a much higher frequency. Embedding these atoms into tiny photonic resonators on a chip makes the clock small enough for practical use. A nuclear clock of this size would not lose a single second over the entire age of the universe. This level of precision would enable navigation systems accurate enough to guide vehicles through centimeter-level obstacles.
From the abstract
While the $^{229}$Th nuclear isomer has recently been observed and laser-excited, converting optical nuclear manipulation into a chip-scale solid-state frequency standard remains an open challenge. Here, we present a nanophotonic platform to realize an all-solid-state nuclear clock based on the low-energy isomeric transition of $^{229}$Th embedded in high-$Q$ fluoride photonic resonators. By coupling ensembles of thorium nuclei to confined optical modes, we show that resonant field build-up in t