Prospects for a Solid-State Nuclear Clock

TL;DR

This paper reviews the current state and future prospects of solid-state nuclear clocks based on Thorium-229, highlighting recent breakthroughs, challenges, and potential for highly precise timekeeping using nuclear transitions in crystal hosts.

Contribution

It discusses the feasibility of a solid-state nuclear clock using Th-229's low-energy transition, addressing key physical challenges and technological considerations.

Findings

Recent experimental progress in Th-229 nuclear clock development

Identification of inhomogeneous broadening as a major challenge

Potential for extremely precise timekeeping with solid-state nuclear clocks

Abstract

Motivated by recent experimental breakthroughs toward a realization of a solid-state Thorium-229 nuclear clock, we review the technology, basic physics motivation, and limitations of the present generation of atomic clocks. We then discuss prospects for a new generation of clocks based on an anomalous low-energy 8.4 eV nuclear transition in Th-229, with an extremely long lifetime of 641 seconds when doped into CaF crystals. To realize such solid-state nuclear clocks one must confront basic nuclear, AMO, and solid state physics questions. Key challenges are understanding and minimizing the effects of inhomogeneous broadening, associated with strains and electric field gradients due to both the Th dopants and intrinsic crystal defects.