New Atomic Clock Is Most Precise Timekeeper Ever, Scientists Say

 @rpalmerscience on January 22 2014 2:07 PM
67431
An experimental atomic clock that uses strontium atoms held in a lattice of laser light is the world's most precise and stable atomic clock, scientists say. (This image is a composite of photos, enhanced to make the lasers more visible.) Ye group and Baxley/JILA

A newly unveiled atomic clock is the most precise timekeeping device yet, and perfect for anyone who wants to make sure their train arrives on schedule -- down to the 1/430 trillionth of a second. 

The new clock was unveiled by researchers from the University of Colorado Boulder and the National Institute of Standards and Technology – the federal agency best known as the official timekeeper for America – in the journal Nature on Wednesday. The timepiece, based on the element strontium, is expected to keep a steady time, neither gaining nor losing a second, for at least 5 billion years.

“This single clock has simultaneously achieved the best known performance in the key characteristics necessary for consideration as a primary standard: stability and accuracy,” the authors wrote in Nature.

You might wonder: How do you keep time with atoms, anyway? The “tick” and “tock” of an atomic clock is actually electrons jumping between different energy states inside an atom, after being exposed to certain kinds of radiation, such as radio waves. Currently, our time standard is based on a cesium clock: One second equals around 9.2 billion cycles of the radiation that causes a cesium atom to oscillate between two energy states.

While a cesium clock is quite precise, it’s not the most precise atomic clock – it errs by about .03 nanoseconds every day, so it’s expected to lose one second every 100 million years.

The new strontium clock, currently housed at the JILA (a joint institution of NIST and the University of Colorado), is made with a few thousand atoms of strontium. The atoms are held together in a column by a series of laser light cages called an optical lattice. Researchers saturate the strontium atoms with red laser light that kickstarts the oscillation between energy levels, which occurs 430 trillion times per second.

The team compared the performance of a strontium clock from 2005 and one built in 2013 to see how well they synchronized. They matched up precisely.

"We already have plans to push the performance even more," researcher Jun Ye said in a statement. "So in this sense, even this new Nature paper represents only a 'mid-term' report. You can expect more new breakthroughs in our clocks in the next five to 10 years."

The strontium clock isn’t the only high-performing timepiece that NIST and UCB have up their sleeves. Just last year, they introduced another atomic clock based on the element ytterbium that performs similarly to the strontium clock.

“Exquisitely precise timing is built into every aspect of modern infrastructure,” NIST official Thomas O’Brian told the New Yorker recently. “GPS, smartphones, computer networks, the Internet, electrical power — these all require synchronization down to the billionth of a second.”

Naturally, you might wonder what technological marvels might we work with clocks ticking in hundreds of trillionths of seconds? Only time will tell.

SOURCE: Bloom et al., “An optical lattice clock with accuracy and stability at the 10^-18 level.” Nature published online 22 January 2014.

Join the Discussion