Scientists Unveil Atomic Clock That Could Redefine the Second

Scientists have developed the world's most accurate atomic clock, a device so precise it has the potential to redefine the second. Researchers at Singapore's Centre for Quantum Technologies (CQT) have created a timekeeping device capable of measuring time to trillionths of a second, achieving a precision of 19 decimal places.

The clock, constructed using the element lutetium, reportedly surpasses previous record holders built with other elements. According to its creators, the device is so reliable that it would take more than 260 billion years to lose a single second. "I am confident that what we have now is the most accurate clock in the world," said team leader Murray Barrett from the National University of Singapore.

Atomic clocks function by monitoring atomic transitions, specifically when an atom's electrons change energy levels. The frequency of this transition is a fixed atomic property. A laser is matched to this transition, and its light oscillations are used to count time, much like a pendulum. This method has been the basis for timekeeping for decades, with cesium atoms forming the global standard since the 1960s and supporting systems like GPS.

However, scientists have been exploring other elements, such as ytterbium, strontium, and aluminum, which oscillate faster than cesium, leading to improved accuracy and setting new records. The CQT team began working with lutetium over a decade ago, anticipating its potential for high-performance timekeeping.

The lutetium clock's exceptional performance stems from its atomic properties. Its clock transition is notably resistant to changes in temperature and magnetic fields, factors that can affect the frequency stability of other elements. "The good properties mean that high accuracy can be achieved even in a wide range of environments," Barrett explained. "The lutetium clock would be stable even if you went from the hottest place recorded on Earth in Death Valley to the coldest place in the Antarctic plateau."

The researchers have spent over ten years on precision engineering and testing the lutetium atomic clock. They verified its accuracy by comparing two lutetium clocks, which matched to the 19th decimal place, a comparison the team describes as the most precise ever performed.

Future advancements aim to miniaturize the lab-scale clock into a transportable system without compromising its accuracy. The researchers believe these advanced clocks could contribute to answering fundamental questions in physics, detecting minute changes in gravity, and ultimately reshaping the definition of the second. The international body responsible for time standards is expected to consider data from new optical atomic clocks for a potential redefinition of the second in or after 2030. This lutetium clock has independently verified its accuracy at the 19th decimal place, a feat not previously achieved by an optical clock.

Optical clocks are highly precise atomic clocks that utilize light frequencies for time measurement, distinguishing them from traditional microwave-frequency clocks. They are among the most accurate timekeeping devices currently available and are crucial for applications such as GPS, navigation, mapping Earth's gravity, and fundamental physics research. They also play a key role in refining time standards, including the potential redefinition of the second.