Scandium-45: The Key to Clocks More Precise Than Atomic Ones ⚡ экспресс
The nuclear transition in ⁴⁵Sc from the ground state to the isomeric state at 12.389 keV has a lifetime of 0.46 s, a natural width of 1.4 feV, and a quality factor of ~10^19 — surpassing the accuracy of the best atomic clocks. Using the European X-ray Free-Electron Laser, the isomer lifetime was measured via delayed incoherent Kα,β fluorescence, and for the first time, elastic fluorescence was detected, allowing determination of the partial internal conversion coefficient of 390(60). The absence of a nuclear forward scattering signal with delays exceeding 2 ms indicates line broadening by the environment by at least 500 times relative to the natural width (>500Γ₀). These results set experimental constraints on decoherence mechanisms in solids and represent an important milestone toward solid-state nuclear clocks.
Hidden inside the scandium-45 nucleus is a nearly perfect pendulum. Its oscillations — the emission of X-rays — are so steady that it ticks 10^19 times in half a second without ever missing a beat. That’s billions of times more stable than the best atomic clocks.
Scientists 'listened' to this pendulum by exciting the nuclei with an X-ray laser and using spectroscopy and light measurement. However, in a solid crystal, neighboring atoms jiggle like a wobbly table under a pendulum. This disorder from vibrations blurs the signal at least 500-fold, muddying the clock’s ideal rhythm. Even under these conditions, scandium-45 remains a record-breaker.
A nuclear clock based on it would notice a shift in time if raised by just one centimeter — gravity’s hand, just as Einstein predicted. This means we could not only improve navigation but also test whether the laws of physics have changed over billions of years.
🎯 Nuclear clocks based on scandium-45 will be so sensitive they'll show that time runs faster on the second floor than on the first.