Atomic clocks use quantum physics and the resonant frequency of atoms, like cesium, to define time. Modern timekeeping relies on the accuracy of atomic clocks, which revolutionized timekeeping by ...

The most precise clocks ever built are now testing Einstein, hunting dark matter, and reshaping how we define time itself. The world’s most precise clocks are changing how we understand time itself: ...

For many years, cesium atomic clocks have been reliably keeping time around the world. But the future belongs to even more accurate clocks: optical atomic clocks. In a few years' time, they could ...