L. A. M. Johnson

Frequency ratio of the 229mTh nuclear isomeric transition and the 87Sr atomic clock

Laser Excitation of the Th-229 Nucleus

Frequency Ratio of Two Optical Clock Transitions inYb+171and Constraints on the Time Variation of Fundamental Constants

Absolute frequency measurement of the²S_1/2–²F_7/2electric octupole transition in a single ion of¹⁷¹Yb⁺with 10⁻¹⁵fractional uncertainty