What limits the accuracy of a solid-state thorium nuclear clock?
In plain words
Thorium-229 nuclei embedded in a transparent crystal can be laser-excited, which could make a clock that is compact and insensitive to many disturbances. The crystal environment broadens and shifts the line, and the ultimate accuracy is unknown.
Precise statement
For Th-229 in CaF2, LiSrAlF6 or ThF4 hosts, identify the mechanisms (temperature-dependent electric-field gradients, inhomogeneous broadening from charge-compensating defects, isomer quenching by radiation-induced defects) limiting linewidth and frequency reproducibility, and determine the achievable fractional uncertainty of a solid-state nuclear clock.
What would settle it
Repeated measurements across crystals and temperatures with a closed-loop nuclear clock compared to an optical clock, giving a reproducibility budget below 1e-17.
Status in the literature
Unverified note
Temperature sensitivity was measured in 2024, crystal-to-crystal reproducibility in 2025, and a Th-229 nuclear clock with feedback loop was reported in June 2026.