By measuring the tiny shifts of oscillation frequency in these ultra precise clocks, researchers are able to explore the influences of Einstein's theory of relativity on quantum systems.

So steady are these oscillations that atomic clocks keep better time than the spinning earth itself The "pendulums" which regulate them are the vibrating parts of atoms or molecules.

En-route to nuclear clocks, researchers have found a resonant mode in thorium atom nuclei with a low temperature coefficient - nuclear oscillators are ...