| Larissa Bilovits
|
11.09.2024
The Vienna University of Technology successfully researched a method that can be used to make highly precise measurements. This could also be groundbreaking for other research fields.
Atomic clocks are considered to be the most precise timekeepers in the world. The state of the art in this field has hardly changed for many decades. Now the Technical University (TU) Vienna However, there was a research breakthrough: the world’s first atomic nucleus clock.
Thorium as a clock
After the scientists had been working towards this for decades, things now happened quite quickly: After the team around Professor Thorsten Schumm After they had only announced in April this year that they had succeeded in switching an atomic nucleus from one state to another using a laser, this effect of high-precision measurement could now already be implemented in practice.
The TU researchers, together with US colleagues from Joint Institute for Laboratory Astrophysics (JILA) and from National Institute of Standards and Technology (NIST)to combine a high-precision optical atomic clock with a high-energy laser system. They coupled this to a crystal containing thorium atomic nuclei, which in turn are used as a clock.
So far, however, the clock does not tick more accurately than a conventional atomic clock – nor was that the goal of this first step. “The first prototype has now proven that thorium can be used as a clock for ultra-high-precision measurements. The rest is technical development work, and no major obstacles are to be expected,” explains Thorsten Schumm.
Less susceptible to disruption
The special thing about an atomic nucleus clock is that it is much less susceptible to interference than an atomic clock because atomic nuclei are much smaller and therefore react less strongly to external electromagnetic fields. What has presented researchers with challenges so far, however, is that switching the states of the atomic nuclei requires at least a thousand times more energy than the photons of a laser have.
The only known exception is thorium.”Thorium nuclei have two states of very similar energy, so you can switch them using lasers,” says Schumm. “But to do this, you have to know the energy difference between these two states very precisely. For many years, research teams all over the world have been looking for the exact value of this energy difference in order to be able to switch thorium nuclei in a targeted manner – we have succeeded in doing this for the first time, and this is the result we were able to publish in April.”
Many other possible applications
The precision that has been researched with the technology surrounding thorium nuclei could also lead to important advances in other research areas in addition to time measurement, such as geology or astrophysics. For example, it is hoped that the extreme precision will now enable the fundamental laws of nature to be examined more closely. It could be investigated whether the natural constants are perhaps not so perfectly constant after all, but may also change in space and time.
