Host-Dependent Frequency Offsets in ^{229}Th Nuclear Clockwork.

Area of Science:

• Atomic Physics
• Quantum Technology
• Nuclear Physics

Background:

• Advances in laser excitation of the low-energy nuclear isomer transition in Thorium-229 (²²⁹Th) enable novel nuclear clock development.
• Nuclear clocks offer exceptional performance and sensitivity to exotic physics.

Purpose of the Study:

• Investigate the host dependence of the ²²⁹Th nuclear clock frequency.
• Analyze the isomer shift, which arises from differences in nuclear charge distribution between ground and excited states.

Main Methods:

• Combine relativistic many-body atomic structure methods with periodic density functional theory.
• Evaluate isomer shifts in solid-state hosts, considering the crucial "relaxation" effect.

Main Results:

• Predict nuclear clock frequencies for solid-state and trapped ion platforms (²²⁹Th⁴⁺, ²²⁹Th³⁺).
• Determine the bare ²²⁹Th nucleus transition energy.
• Constrain ²²⁹Th nuclear transition frequencies to an 80-MHz window using calculated isomer shifts.

Conclusions:

• The host material significantly influences the ²²⁹Th nuclear clock frequency.
• Calculated shifts aid experimental searches for the ²²⁹Th nuclear transition in novel materials, advancing quantum clock technology.