Ytterbium
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Scientists set new stability record with ytterbium atomic clock
The story of scientific advancement is rarely one of leaps and bounds. More often than not it's evolution over revolution, and the story of the so-called ytterbium atomic clock fits that bill perfectly. You may remember that in July researchers improved upon the standard, cesium-powered atomic clock model by using a network of lasers to trap and excite strontium; instead of losing a second every few years, the Optical Lattice Clock only lost a second every three centuries. Researchers at the National Institute of Standards and Technology made a pretty simple tweak to that model: replace the strontium with ytterbium and, voilà, another ten-fold increase in stability. Ten thousand of the rare-earth atoms are held in place, cooled to 10 microKelvin (just a few millionths of a degree above absolute zero) and excited by a laser "tick" 518 trillion times per second. Whereas the average cesium atomic clock must run for roughly five days to achieve its comparatively paltry level of consistency, the ytterbium clock reaches peak stability in just a single second. That stability doesn't necessarily translate into accuracy, but chances are good that it will. That could could mean more accurate measurements of how gravity effects time and lead to improvements in accuracy for GPS or its future equivalents. The next steps are pretty clear, though hardly simple: to see how much farther the accuracy and stability can be pushed, then shrink the clock down to a size that could fit on a satellite or space ship. The one currently in use at the NIST is roughly the size of a large dining room table.
Researchers capture a single atom's shadow, has implications for quantum computers
A very small atom can cast a very large shadow. Well, not literally, but figuratively. Researchers at Griffith University have managed to snap the first image of a single atom's shadow and, while the dark spot may be physically small, the implications for the field of quantum computing are huge. The team of scientists blasted a Ytterbium atom suspended in air with a laser beam. Using a Fresnel lens, they were able to snap a photograph of the dark spot left in the atom's wake as the laser passed over it. The practical applications could improve the efficiency of quantum computers, where light is often used to transfer information. Since atoms have well understood light absorption properties, predictions can be made about the depth of a shadow cast, improving communication between the individual atoms performing calculations. The research could even be applied to seemingly mundane and established fields like X-Ray imaging, by enabling us to find the proper intensity levels to produce a quality image while minimizing damage to cells. For more info, check out the current issue of Nature.
