Gadget in extremis: Experimental atomic clocks set new accuracy record
The organisation describes the clocks as acting like 21st-century pendulums or metronomes, ones that could swing back and forth with perfect timing. For a period comparable to the age of the universe!
NIST’s ultra-stable ytterbium lattice atomic clock. Ytterbium atoms are generated in an oven (large metal cylinder on the left) and sent to a vacuum chamber in the center of the photo to be manipulated and probed by lasers. Laser light is transported to the clock by five fibers (such as the yellow fiber in the lower center of the photo).
NIST physicists report in the Aug. 22 issue of Science Express that the ytterbium clocks’ tick is more stable than any other atomic clock. Stability can be thought of as how precisely the duration of each tick matches every other tick. The ytterbium clock ticks are stable to within less than two parts in 1 quintillion (1 followed by 18 zeros), roughly 10 times better than the previous best published results for other atomic clocks.
This dramatic breakthrough has the potential for significant impacts not only on timekeeping, but also on a broad range of sensors measuring quantities that have tiny effects on the ticking rate of atomic clocks, including gravity, magnetic fields, and temperature. And it is a major step in the evolution of next-generation atomic clocks under development worldwide, including at NIST and at JILA, the joint research institute operated by NIST and the University of Colorado Boulder.
“The stability of the ytterbium lattice clocks opens the door to a number of exciting practical applications of high-performance timekeeping,” said NIST physicist Andrew Ludlow. Egg timing will not be one of them!
Apparently, with atomic clocks, the ticks must be averaged over a period to provide the best results, and one important benefit of the ytterbium clocks is that precise results can be achieved very quickly. For example, writes NIST, the current U.S. civilian time standard – the NIST-F1 cesium fountain clock – must be averaged for about 400,000 seconds (about five days) to achieve its best performance. The new ytterbium clocks achieve that same result in about one second of averaging time.