Gadget-in Extremis: Atomic clocking the effects of gravity

The new clock was built at JILA, which is a joint institution of the National Institute of Standards and Technology (NIST) and the University of Colorado Boulder. And the one of the implications is that a much more precise definition of an official second is possible, and also that new applications for such clocks become feasible.

“Enabling pinpoint navigation in the vast expanse of space as well as searches for new particles, this clock is the latest to transcend mere timekeeping. With their increased precision, these next-generation timekeepers could reveal hidden underground mineral deposits and test fundamental theories such as general relativity with unprecedented rigor. For atomic-clock architects, it’s not just about building a better clock; it’s about unraveling the secrets of the universe and paving the way for technologies that will shape our world for generations to come.”

Optical lattice

I won’t pretend to understand the workings of the instrument, but apparently an extremely cold gas of strontium atoms is trapped in an optical lattice, a “web of light”, explains JILA. The atoms are held in an ultrahigh-vacuum environment, which means no other gases present. This vacuum helps preserve the atoms’ delicate quantum states (the red dot you see in the image above is a reflection of the laser light used to create the atom trap, explains the organisation).

By trapping and measuring tens of thousands of individual atoms simultaneously the system enables a huge advantage in precision. The more atoms measured, the more data the clock has for yielding a precise measurement of the second, says JILA.

“To achieve new record-breaking performance, the JILA researchers used a shallower, gentler “web” of laser light to trap the atoms, compared with previous optical lattice clocks. This significantly reduced two major sources of error — effects from the laser light that traps the atoms, and atoms bumping into one another when they are packed too tightly.”

Second

It is not the first time – ahem, see Raspberry Pi, Arduino motor their way to artistic alternative time display – that we’ll mention the scientific community is considering redefining the second, that familiar international unit of time. And these “next-generation” optical atomic clocks should have a role to play…

“Existing-generation atomic clocks shine microwaves on atoms to measure the second. This new wave of clocks illuminates atoms with visible light waves, which have a much higher frequency, to count out the second much more precisely. Compared with current microwave clocks, optical clocks are expected to deliver much higher accuracy for international timekeeping — potentially losing only one second every 30 billion years.”

Pictured above is a close-up of the scientific instrument. The researchers – Alexander Aeppli, Kyungtae Kim, William Warfield, Marianna S. Safronova and Jun Ye – describe their work in Physical Review Letters.

“If we want to land a spacecraft on Mars with pinpoint accuracy, we’re going to need clocks that are orders of magnitude more precise than what we have today in GPS,” said Ye. “This new clock is a major step towards making that possible.”

“We’re exploring the frontiers of measurement science. When you can measure things with this level of precision, you start to see phenomena that we’ve only been able to theorize about until now.”

See also: Gadget in Extremis – Breaking world record data transmission speed