For decades, the world has kept time with the ticks of atomic clocks.
But they could soon be a thing of the past, thanks to the introduction of a nuclear clock that could revolutionise how we measure time.
An international team has demonstrated the key elements of the device, which paves the way for ultra-precise timekeeping.
The clock works by using signals from the nucleus, or core, of an atom.
The team used a specially designed ultraviolet laser to precisely measure the frequency of an energy jump in the nuclei of thorium – a naturally occurring metal – embedded in a solid crystal.
For decades, the world has kept time with the ticks of atomic clocks. But they could soon be a thing of the past, thanks to the introduction of a nuclear clock (artist’s impression) that could revolutionise how we measure time
They also employed an optical frequency comb, which acts like an extremely accurate light ruler, to count the number of ultraviolet wave cycles that create this energy jump.
This transition from one similar energy state to another – which takes place very rapidly – is what allows for high-precision measurements.
While this laboratory demonstration is not a fully developed nuclear clock, it contains all the core technology for one, the researchers said.
Nuclear clocks could be much more accurate than current atomic clocks, which provide official international time and play major roles in technologies such as GPS, internet synchronization, and financial transactions.
For the general public, this development could ultimately mean even more precise navigation systems, faster internet speeds, more reliable network connections, and more secure digital communications.
Beyond everyday technology, nuclear clocks could improve tests of fundamental theories for how the universe works, potentially leading to new discoveries in physics.
They could help detect dark matter or verify if the constants of nature are truly constant, allowing for verification of theories in particle physics without the need for large-scale particle accelerator facilities.
The team used a specially designed ultraviolet laser to precisely measure the frequency of an energy jump in the nuclei of thorium – a naturally occurring metal – embedded in a solid crystal
The researchers said a nuclear clock would have major advantages for clock precision over current technology.
Atomic clocks measure time by tuning laser light to frequencies that cause electrons to jump between energy levels.
However, compared with the electrons in atomic clocks, the mechanisms within a nuclear clock are much less affected by outside disturbances such as stray electromagnetic fields.
The laser light used in a nuclear clock is also much higher in frequency than that required for atomic clocks.
This leads to more ‘ticks’ per second and therefore more precise timekeeping.
The team involved researchers from the National Institute of Standards and Technology in Maryland and the University of Colorado Boulder.
Jun Ye, one of the study’s authors, said: ‘Imagine a wristwatch that wouldn’t lose a second even if you left it running for billions of years.
‘While we’re not quite there yet, this research brings us closer to that level of precision.’
Thorsten Schumm, another author, said: ‘With this first prototype, we have proven: Thorium can be used as a timekeeper for ultra-high-precision measurements.
‘All that is left to do is technical development work, with no more major obstacles to be expected.’
The findings were published in the journal Nature.
