Cool Optical Lattice Clocks are 1000 Times more Precise Than the Cesium Atomic Clock

Time keeping may be getting a bit more precise. Researchers have found that two cryogenically cooled optical lattice clocks can be synchronized to a tremendous one part in 2.0 x 10-18, which means that they would only go out of sync by a second in 16 billion years.

The new clocks are about 1,000 times more precise than the current international timekeeping standard cesium atomic clock. They were created with atoms of strontium held in a laser-generated optical lattice with a wavelength that allows for precise measurement. At this wavelength, the laser-generated optical lattice does not affect the atoms. The containers are cooled to -180 degrees Celsius to eliminate perturbations from blackbody radiation, as well.

"It was a great feeling to have shown this excellent agreement between the clocks," said Hidetoshi Katori, one of the researchers, in a news release. "If we can miniaturize this technology 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. 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."

These clocks could be pivotal in opening clock-based geodesy, which could measure the shape of the Earth. This takes advantage of the fact that in accordance with Einstein's general principle of relativity, clocks in a strong gravitational field will tick more slowly than those in a lower field. It may be possible by using the tiny difference to make measurements of the strength of the gravitational potential at different locations and different times, creating a new role for clocks beyond their traditional role as time-keepers.

The findings are published in the journal Nature Photonics.

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