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Optical quantum clocks developed at the University of Adelaide have been proven to outperform GPS navigation systems by many orders of magnitude. The clocks, which were put through their paces in naval exercises, were designed to be robust enough to withstand being rocked by waves while they are on ships.

Previous versions of clocks that operate at this level of accuracy are not portable, as they require large amounts of lab space and are too sensitive to motion and changes in temperature.

The clocks were developed by a team led by the University of Adelaide's Professor Andre Luiten, Chief Innovator and Chair of Experimental Â鶹ÒùÔºics at the Institute of Photonics and Advanced Sensing (IPAS), in partnership with colleagues at the Defense Science and Technology Group (DSTG).

"Assured timing is critical for communications and positioning applications, especially at a time when sovereign defense capability is of increasing importance," Professor Luiten said.

"Timing signals are currently provided by the Global Positioning System (GPS). However, in contested environments, where GPS may be jammed or spoofed, time synchronization between locations would rapidly deteriorate. A solution to this issue for the Australian Defense Force (ADF) is a sovereign-developed, rugged and portable clock, which could be deployed in the field.

"The cutting-edge generation of clocks developed by the IPAS and DST team are between 20 and 200 times more precise over a second of measurement time than the present international standard," said Dr. Ashby Hilton, research physicist from the IPAS team. Both clocks are optical atomic clocks, using the elements rubidium and ytterbium to provide incredibly pure timing signals, which enable superior performance to GPS clocks.*

The clocks designed by the team rely on sealed cells containing a low-pressure gas of atoms. These cells are then interrogated with lasers at specific colors, and the information extracted is used to steer the laser wavelength to the atom—providing stability.

The clocks were deployed, along with other quantum sensing and timing technologies, at the Rim of the Pacific (RIMPAC) naval exercises in July 2022, off Hawaii, as part of an alternative position, navigation and timing challenge that pitted them against technology developed by other countries.

The full results from the field tests have now been in the journal Nature Communications.

"RIMPAC was the first time that an ensemble of optical atomic clocks was demonstrated at sea, a significant milestone for assured timing and navigation," said Ashby. "The best quantum technologies from around the globe were installed within a shipping container during this exercise and spent more than three weeks on maneuvers. The University of Adelaide's clocks were at the top of the performance chain of all clocks included in the exercise."

While the clocks have been designed for this very specific application, future variants could have other uses, like next-generation GPS satellite constellations or accurate record keeping in high-frequency financial trading.

The university has partnered with Quantx Labs, a local quantum technologies company, with the goal of transferring the IP and know-how out of the research space and into industry.