JILA develops laser-based ‘world’s most accurate’ atomic clock

02 Jul 2024

Developers used shallow “web” of laser light to trap atoms, instead of previous optical lattice.

Scientists have developed an atomic clock that is more precise and accurate than any clock previously created. The new clock was built by researchers at JILA, a joint institution of the National Institute of Standards and Technology (NIST) and the University of Colorado Boulder.

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.

The worldwide scientific community is considering redefining the second, based on these next-generation optical atomic clocks.

Existing-generation atomic clocks shine microwaves on atoms to measure the second. But 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.

‘Optical web’

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 reduces 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.

“This clock is so precise that it can detect tiny effects predicted by theories such as general relativity, even at the microscopic scale,” said NIST and JILA physicist Jun Ye. “It’s pushing the boundaries of what’s possible with timekeeping.”

This new clock design can allow detection of relativistic effects on timekeeping at the submillimeter scale. Raising or lowering the clock by that minuscule distance is enough for researchers to discern a tiny change in the flow of time caused by gravity’s effects.

This ability to observe the effects of general relativity at the microscopic scale can significantly bridge the gap between the microscopic quantum realm and the large-scale phenomena described by general relativity.

Navigating space and quantum advances

More precise atomic clocks also enable more accurate navigation and exploration in space. With space travel, even tiny errors in timekeeping can lead to navigation errors that grow exponentially the further one travels.

“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,” added Ye. “This new clock is a major step towards making that possible.”

The same methods used to trap and control the atoms could also produce breakthroughs in quantum computing, says the team. Quantum computers need to be able to precisely manipulate the internal properties of individual atoms or molecules to perform computations.

By venturing into the microscopic realm where the theories of quantum mechanics and general relativity intersect, researchers say they are “cracking open a door to new levels of understanding about the fundamental nature of reality itself.”

The work is described in a preprint accepted for Physical Review Letters, available at arxiv.org.