It May Be Time For Real-World Applications Using Atomic Clocks

According to a university press release, new technologies created at the University of Birmingham-led UK Quantum Technology Hub Sensors and Timing are helping to reduce the size of quantum, or atomic, clocks.

A group of quantum physicists have developed new methods that not only shrink the size of their clock but also make it durable enough to be taken outside of the lab and used in the "real world," working in collaboration with and receiving funding from the UK's Defence Science and Technology Laboratory (Dstl).

For more accurate approaches to fields like worldwide internet communications, navigational systems, or international stock trading, where fractions of seconds might make a significant economic impact, quantum - or atomic clocks are commonly regarded as vital. The standard (SI) unit of measurement may be redefined if atomic clocks with optical clock frequencies were 10,000 times more precise than their microwave equivalents.

In the future, even more, sophisticated optical clocks may have a substantial impact on both daily living and basic science. They provide more resilience for the nation's timing infrastructure by enabling longer intervals before needing to resynchronize than other types of clocks, and they open up potential positioning and navigation uses for autonomous cars. These clocks' unmatched accuracy can also aid in our ability to look beyond the confines of conventional physics and comprehend some of the most puzzling features of the cosmos, such as dark matter and dark energy. These clocks will also aid in addressing issues with fundamental physics, such as whether the fundamental constants are indeed constants or change over time.

The study's principal investigator, Yogeshwar Kale, stated: "Optical clocks are essential to many future information networks and communications because of their stability and accuracy. We may use them, for instance, in on-ground navigation networks where all such clocks are connected through optical fibre and have begun communicating with one another, once we have a system that is ready for usage outside of the laboratory. These networks will lessen our reliance on GPS devices, which can occasionally malfunction.

“These transportable optical clocks not only will help to improve geodetic measurements – the fundamental properties of the Earth’s shape and gravity variations – but will also serve as precursors to monitor and identify geodynamic signals like earthquakes and volcanoes at early stages.”

Despite the fact that these quantum clocks are developing quickly, their size—current models fit in a van or a vehicle trailer and have a volume of roughly 1500 litres—and sensitivity to environmental factors make it difficult to carry them to other locations.

The Birmingham team, which is part of the UK Quantum Technology Hub Sensors and Timing, has developed a method to overcome both of these difficulties in a container that is around 120 litres in volume and weighs less than 75 kilogrammes. Published in Quantum Science and Technology is the work.

A spokesperson for Dstl added: “Dstl sees optical clock technology as a key enabler of future capabilities for the Ministry of Defence. These kinds of clocks have the potential to shape the future by giving national infrastructure increased resilience and changing the way communication and sensor networks are designed. With Dstl’s support, the University of Birmingham have made significant progress in miniaturising many of the subsystems of an optical lattice clock, and in doing so overcame many significant engineering challenges. We look forward to seeing what further progress they can make in this exciting and fast-moving field.”

The clocks generate and then detect atomic quantum oscillations using lasers. These oscillations can be monitored very precisely, and since the frequency can be calculated, so can the time. Reducing external impacts on the measurements, such as mechanical vibrations and electromagnetic interference, is a difficulty. The measurements must be made in a vacuum with little influence from the outside world in order to achieve that.

An ultra-high vacuum chamber, the smallest one yet employed in the field of quantum timekeeping, is at the centre of the new design. The atoms may be trapped in this chamber and cooled to a temperature extremely near to "absolute zero" such that they can be utilised as precise quantum sensors.

The group showed that they could fill the chamber with about 160.000 very cold atoms in less than a second. Additionally, they demonstrated that the system could be transported over 200 kilometres before being set up and prepared to take measurements in less than 90 minutes. During the travel, the system was able to withstand a spike in the temperature of 8 degrees over ambient temperature.

Kale added: “We’ve been able to show a robust and resilient system, that can be transported and set up rapidly by a single trained technician. This brings us a step closer to seeing these highly precise quantum instruments being used in challenging settings outside a laboratory environment.”