Standard units are among the most important inventions ever as it is only possible with them to measure and analyze the world around us. For that reason researchers are continually looking for new ways to make measurements, as one method may have more potential than another. Researchers at the University of California, Berkeley and Berkeley Lab have developed a new method for measuring time, which is quite clever.
Modern atomic clocks work by counting the number of transitions an electron makes from one orbit to another within an atom, and the second is actually defined as so many transitions for a specific transition within a cesium atom. What the researchers have developed is also an atomic clock but instead of measuring electron transitions it measures the frequency of atoms. Quantum mechanics tells us that mass exists as a wave-particle duality, so every particle, including atoms, have a frequency typically ten billion times greater than frequencies of visible light, called the Compton or de Broglie frequency. To harness this property of matter, the researchers created an atomic interferometer which takes two identical atoms and moves one while keeping the other still. Relativity tells us that the movement of the one causes its frequency to shift, and that shift the researchers have transitioned to a laser which can then be measured.
This first iteration of the clock is comparable in precision to the first atomic clocks developed 60 years ago, but could one day be improved to match the most precise clocks in existence. Potentially it could have other uses too, such as defining the kilogram and even analyzing the properties of antimatter.