An international research team is advancing precision timekeeping by developing a nuclear clock using thorium isotopes and innovative laser methods, potentially transforming our understanding of physical constants and dark matter. (Artist’s concept.) Credit: SciTechDaily.com
A new and more precise way of measuring time is the aim of an international research project in which Würzburg physicist Adriana Pálffy-Buß is involved. The results could also help in the search for dark matter.
The global navigation system ![Thorium Nuclear Clock](https://scitechdaily.com/images/Thorium-Nuclear-Clock-777x395.jpg)
The jump of a thorium nucleus from the excited to the ground state is the starting point of a new type of clock that research teams from Würzburg and Vienna want to develop. Credit: Oselote / iStockphoto (Atomkern) /KI Hintergrund), Edited
Increasing the Measurement Accuracy of Physical Methods
“Researchers led by Oliver Heckl from the University of Vienna want to increase the measurement Related Post Crocodiles are drawn to the wails of crying human babies and infant primates
accuracy
How close the measured value conforms to the correct value.
” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]” tabindex=”0″ role=”link”>accuracy of physical methods in the special research area ‘Coherent Metrology beyond Electric Dipole Transitions’. An innovative method that uses light with orbital angular momentum will be used,” according to the FWF press release. What does this mean?
“The most precise timekeepers today are atomic clocks, which measure time based on the frequency of the transitions that electrons make between the different energy levels of an Related Post What causes you to get a 'stitch in your side'?
photon
A photon is a particle of light. It is the basic unit of light and other electromagnetic radiation, and is responsible for the electromagnetic force, one of the four fundamental forces of nature. Photons have no mass, but they do have energy and momentum. They travel at the speed of light in a vacuum, and can have different wavelengths, which correspond to different colors of light. Photons can also have different energies, which correspond to different frequencies of light.
” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]” tabindex=”0″ role=”link”>photon was achieved in 2023.
Shoot thorium atoms with a laser and capture the photons you are looking for: Unfortunately, the “nuclear clock” doesn’t work that easily. One of the reasons for this: “You need around eight electron volts to excite the nucleus. However, six electron volts are enough to remove the outermost electron from its orbit. In this case, the excited nucleus prefers to transfer its surplus energy to the electron instead of emitting a photon. However, this must be avoided,” explains the physicist.
The solution to this problem could be to incorporate thorium atoms into special transparent crystals. “The corresponding experiments showed that thorium takes its place in the crystal lattice in an ionic state – in other words, it gives up its outer electron,” explains Pálffy-Buß. The crystal can also host many thorium nuclei at once, which makes it easier to detect the photon being sought.
Laser pulses in the form of a rotating corkscrew are intended to bring the thorium nuclei into the desired excited state. Credit: Tobias Kirschbaum
Rotating Corkscrews As Solution
Another problem: to date, there is no laser with the necessary precision to trigger the desired effect. The Austrian-German research team is therefore relying on the aforementioned “innovative method that uses light with orbital angular momentum.” This is also referred to as twisted light or vortex beams.
In very simplified terms, laser pulses do not hit the thorium atoms like an “energy wall” in this method. Instead, they resemble a kind of rotating corkscrew and are therefore more likely to put the atomic nuclei into the desired excited state.
Theory Calculations for the Ideal Scenario
As an expert in theoretical physics, Adriana Pálffy-Buß will primarily support the research project with her calculations. “I design and simulate what would happen in various experimental set-ups and make proposals what would work best,” summarizes the physicist. Among numerous approaches, she tries to identify the most promising scenario. For that, she receives around 375,000 euros from the special research area’s funding pot – enough to finance two doctoral positions.
For physicists, this research project is super exciting, says Pálffy-Buß. “A nuclear clock would make it possible to investigate concepts that are normally taken for granted, such as the question of whether fundamental physical constants are really constant.” It could also help to answer the question of what dark matter is made of. “Due to the fundamental interactions that play a role in nuclear transitions, the nuclear clock is in a unique position to answer such questions,” concludes the physicist.