Mit Laser angeregter Atomkern: Ein Durchbruch nach Jahrzehnten

Physicists have been hoping for this moment for a long time: for many years, scientists all around the world have been searching for a very specific state of thorium atomic nuclei that promises revolutionary technological applications. It could be used, for example, to build an nuclear clock that could measure time more precisely than the best atomic clocks available today. It could also be used to answer completely new fundamental questions in physics – for example, the question of whether the constants of nature are actually constant or whether they change in space and time.

Now this hope has come true: the long-sought thorium transition has been found, its energy is now known exactly. For the first time, it has been possible to use a laser to transfer an atomic nucleus into a state of higher energy and then precisely track its return to its original state.

This marks the start of a new exciting era of research: now that the team knows how to excite the thorium state, this technology can be used for precision measurements. „From the very beginning, building an atomic clock was an important long-term goal,“ says Thorsten Schumm. „Similar to how a pendulum clock uses the swinging of the pendulum as a timer, the oscillation of the light that excites the thorium transition could be used as a timer for a new type of clock that would be significantly more accurate than the best atomic clocks available today.“

But it is not just time that could be measured much more precisely in this way than before. For example, the Earth’s gravitational field could be analyzed so precisely that it could provide indications of mineral resources or earthquakes. The measurement method could also be used to get to the bottom of fundamental mysteries of physics: Are the constants of nature really constant? Or can tiny changes perhaps be measured over time? „Our measuring method is just the beginning,“ says Thorsten Schumm. „We cannot yet predict what results we will achieve with it. It will certainly be very exciting.“

Scientific paper: https://doi.org/10.1103/PhysRevLett.132.182501