Overview
- Two independent research teams published papers in Nature on Wednesday showing working nuclear clocks that use lasers to drive transitions in thorium-229 nuclei embedded in calcium fluoride crystals.
- The clocks measure time by probing energy jumps inside the atomic nucleus rather than in the electron shell, a method that is inherently less sensitive to external electric and magnetic fields.
- Both systems currently match the performance of the best atomic clocks but do not yet exceed them, and researchers say specific improvements are required to reach the theoretical advantage of nuclear clocks.
- The TU Wien group in Vienna used higher-concentration, better-optical-quality thorium crystals and ran a dark-matter search that returned a null result while the Tsinghua team in Beijing relied on a stronger laser, showing complementary technical paths forward.
- If combined and refined, the teams say improved crystal growth, more powerful lasers and integrated engineering could yield smaller, more robust timekeepers with uses in navigation, data synchronization, surveying and fundamental-physics tests.