What limits the accuracy of a solid-state thorium nuclear clock? · revision history

Revision 2

Accepted · core change · record

Changes against revision 1:

Title
What limits the accuracy of a solid-state thorium nuclear clock?
Plain
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 · changed · core
Revision 1: 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.
Revision 2: For Th-229 in $\mathrm{CaF_2}$, $\mathrm{LiSrAlF_6}$ or $\mathrm{ThF_4}$ 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.
Settled by · changed · core
Revision 1: Repeated measurements across crystals and temperatures with a closed-loop nuclear clock compared to an optical clock, giving a reproducibility budget below 1e-17.
Revision 2: Repeated measurements across crystals and temperatures with a closed-loop nuclear clock compared to an optical clock, giving a reproducibility budget below $10^{-17}$.
Kind
well-posed
Answer type
identification
References
(empty)
Literature status
open
Status 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.
Posed since
(empty)

Decisions