Tomas Sikorsky

Abstract Solid-state thorium-229 (229Th) nuclear clocks1,2,3,4,5 are set to provide new opportunities for precision metrology and fundamental physics6,7,8. Taking advantage of inherent low sensitivity of a nuclear transition to its environment9, orders of magnitude more emitters can be hosted in a solid-state crystal compared with current optical lattice atomic clocks10.

Abstract Nuclear laser spectroscopy at the 10−12 precision level (Nature 633.8028 (2024): 63–70) determined the fractional change in the nuclear quadrupole moment of 229Th upon excitation, ΔQ0/Q0 = 1.791(2)%. Such high-accuracy nuclear parameters enable stringent tests and refinement of 229Th nuclear models.

Abstract The radioisotope thorium-229 (229Th) is renowned for its extraordinarily low-energy, long-lived nuclear first-excited state. This isomeric state can be excited by vacuum ultraviolet (VUV) lasers and 229Th has been proposed as a reference transition for ultra-precise nuclear clocks. To assess the feasibility and performance of the nuclear clock concept, time-controlled excitation and depopulation of the 229Th isomer are imperative.