New 'Cryogenic' Clock Developed In Japan Accurate For 16 Billion Years


Researchers at the University of Tokyo and Riken research institute have developed a pair of clocks so accurate that they gain or lose one second every 16 billion years. That is 3 billion years more than the age of the actual universe.

The pair of clocks looks nothing like the normal, everyday clocks we use for looking at the time. Instead, the researchers, led by Professor Hidetoshi Katori, have developed a pair of cryogenic optical lattice clocks that look like mainframe computers more than anything else.

To create the clock, the researchers used laser to generate an optical lattice, or a grid-like structure that serves as an "egg tray" for strontium atoms, which use what Katori calls the "magic wavelength" so that the lattice does not affect the atoms during measurement. Also, to eliminate the effect of heat emitted by a nearby opaque object, the researchers cooled the lattice to -180 degrees Celsius and coated the insides in black to prevent even the smallest amount of light from producing reflections.

The result is a pair of devices that can measure the frequency of the vibration of the atoms with an accuracy of 2.0 x 10 -18, or a pair of clocks that are always on the dot for the next 16 billion years.

This is massively more accurate than the cesium atomic clock, which has an accuracy of 30 million years. Cesium atomic clocks measure time based on the microwave frequency of cesium atoms cooled to near absolute zero and have greatly improved time-keeping standards since their discovery in 1955. In comparison, the cesium atomic clock developed by the National Institute of Standards and Technology of the U.S. Department of Commerce does not gain or lose one second in 300 million years.

"It was a great feeling to have shown this excellent agreement between the clocks," said Katori.

The extremely accurate clocks may not have much use in our everyday lives, but as Katori pointed out, clocks with extreme accuracy can prove to be useful beyond telling the time and in fields such as geodetic engineering, earthquake predictions, communication networks, and global positioning systems.

GPS, for instance, requires hyper-precise atomic clocks, since the system determines a user's location by measuring how long it took the signal from the satellite to travel to his location. If the clocks on the satellite and on Earth are not perfectly accurate, the system will not be able to pinpoint the user's exact location.

"If we can miniaturize the technology even further, it would have useful applications since tiny fluctuations in gravitational potential could be used to detect underground resources, underground spaces, and the movement of lava," Katori said. "We also hope that in the future, this will accelerate the movement toward a new definition of the international second, based on optical lattice clocks, to an even more stringent standard than the current definition of the second, which is based on cesium oscillation."

More details about the cryogenic clocks are published in the Nature Photonics journal.

ⓒ 2018 All rights reserved. Do not reproduce without permission.
Real Time Analytics