From Physics.org:
How sound and light act alike—and not—at the smallest scale
https://phys.org/news/2025-11-alike-smallest-scale.html
Research by physicists in Leiden has produced new insights ... and the emerging field of quantum acoustics. ... .. "We saw that sound waves in materials behave in the same way as light, but also slightly differently. With a mathematical model, we can now explain and predict this behavior."
Young's famous double-slit experiment was the first to show that light sometimes behaves like a particle and sometimes like a wave. ... ... The same experiment was later done with particles, showing that all particles can behave both as a particle and as a wave. Over time, the double-slit experiment has been carried out with all sorts of quantum objects—from electrons and neutrons to buckyballs, molecules made of 60 carbon atoms.
Now with sound instead of light
Steenbergen and colleague Löffler wanted to understand exactly how sound behaves on the smallest scale. The double-slit experiment provides valuable insight here. .. In the experiment, the researchers used gigahertz sound waves, vibrating a billion times per second—far above what humans can hear. ... ..
Steenbergen explains, "We then measure the sound with an extremely precise optical scanner. This device can measure sound literally everywhere, including in and in front of the slits. We can measure the height of the sound waves with picometer precision—that's one millionth of a micrometer."
Similarities—and differences
Just like in the double-slit experiments with light, an interference pattern appears at the back: you can clearly see where the sound is reinforced and where it cancels out.
Steenbergen adds, "But if you look closely, you also see that the pattern is not completely symmetrical. Sound waves don't move the same way in all directions. The speed of the waves depends on the angle at which they pass through the material." By developing a mathematical model, the team was able to explain these differences and predict them accurately.
An old experiment opens new doors
Gigahertz sound waves are widely used in telecommunications, especially in 5G devices such as mobile phones. ..as well as in other micro-electronic devices and sensors that use sound.
It also provides insights for the emerging field of quantum acoustics, where sound waves on the tiniest (quantum) scale are used to carry information. In this way, an experiment from centuries ago is opening new doors once again.
Read full article:
How sound and light act alike—and not—at the smallest scale
https://phys.org/news/2025-11-alike-smallest-scale.html