Dark matter. Source: NASA

Researchers from Rice University (USA) and Leiden University (Netherlands) have used magnetic levitation for the first time to search for dark matter — a mysterious substance that makes up about 85% of all matter in the Universe. This experiment opens up new horizons for fundamental physics. The results of the study have been published in Physical Review Letters.

Dark matter does not glow, absorb, or reflect light, so we cannot see it directly. However, it has mass and interacts with the surrounding world through gravity. Astronomers observe its gravitational influence in the motion of stars, the formation of galaxies, and even in the acceleration of the expansion of the Universe. Uncovering the nature of dark matter is like finding the key to understanding the “hidden” part of the cosmos, which largely determines its behavior.

To take the first step toward this, the team created an experiment called POLONAISE. They placed a microscopic neodymium magnet in a special chamber cooled to almost absolute zero. Thanks to the superconducting properties of the materials and the Meissner effect, the magnet began to levitate — literally suspended in the air without any physical contact with the surface.

Illustaration of the experimental setup inside the refrigerator. Source: Physical Review Journals

This “suspended” magnet proved to be extremely sensitive to any external influences. The idea was that if dark matter passed through it, namely its hypothetical vector particles that transmit so-called “dark” forces, different from ordinary electromagnetic forces, this could cause a barely noticeable shift or oscillation that the device would be able to detect.

To understand why this is important, it is worth going into the theory a little deeper. According to one hypothesis, dark matter may consist of vector particles that interact very little with ordinary matter. They create tiny forces that pass through everything — even through the Earth. This kind of “dark matter wind” can slightly push a levitating magnet — and this becomes a clue: something invisible is still nearby.

Although researchers have not yet been able to detect direct traces of dark matter, the very fact that the system is capable of detecting microscopic changes is proof that the method works.

“We are opening up a new path to solving one of the greatest mysteries in physics,” said Dorian Amaral, co-leader of the project. “These detectors are more sensitive than optical or electrical ones: they are not affected by thermal noise and can detect even the weakest signals.”

This experiment proves that magnetic levitation can become a valuable instrument in the search for dark matter, comparable to large scientific facilities such as LIGO/Virgo or KAGRA, which search for gravitational waves. In addition, such a unit is compact and potentially cheaper to manufacture and use.

Although POLONAISE is only the first step, its results not only help narrow down the search for dark matter, but also signal the need to create even more sensitive sensors. This means that we are one step closer to solving one of the oldest mysteries of the cosmos.