New Optical Atomic Clock Poised to Redefine Timekeeping

New process measures time with light.

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How do you lose a second? Let’s count the ways: mind-wandering, lecture-dozing, discovering new cat videos on YouTube — and, apparently, cesium fountains.

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Sees-ee-what? Cesium microwave fountains, a term scientists use to describe the fountain-like motion of cesium atoms (a chemical element) when you perturb them with a special type of oscillator. Never mind the technical particulars, which involve microwave radiation and vacuum chambers and cooling things to a few millionths of a degree above absolute zero, the behavior of atoms in these cesium fountains — specifically how they vibrate — is how we currently measure the SI second, a standard that’s been in place since 1967 when it was defined by the International Committee for Weights and Measures. Cesium fountains are accurate to one second every 100 million years, which, needless to say, is more accurate than your garden variety Casio.

How do you top losing a mere second at a rate roughly 500 times the entire (relatively brief) span anatomically modern humans have walked the planet? With something called an optical lattice clock, reports BBC News: still an atomic clock, but one that subjects strontium atoms (another chemical element, lower on the periodic table) to laser beams to make them vibrate. The result: accuracy to one second every 300 million years, or three times cesium’s precision.

“Laser beams oscillate much faster than microwave radiation, and in a sense we divide time in much shorter intervals so we can measure time more precisely,” said Dr. Jerome Lodewyck, who works at the Paris Observatory in France and is one of the authors of a paper on the process published in Nature. The other important upside of the optical lattice clock, says Lodewyck, is that it’s apparently more stable.

While this all may sound academic, if you could radically shrink an atomic clock (and don’t think we haven’t been trying), you could bring about all kinds of improvements to existing technology, say mobile phones that picked up signals faster or faster GPS signal acquisition, and — since those two improvements would amount to less time cycling — more efficient energy use, ergo longer battery life.

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