Swiss Researchers Announce Breakthrough in Quantum Physics

In a landmark achievement that could fundamentally alter the trajectory of quantum technology, researchers at ETH Zurich, with theoretical support from TU Wien, announced in August 2025 that they had successfully coaxed a macroscopic object into a state of almost pure quantum mechanical behavior at room temperature. This breakthrough, published in the journal Nature Physics, overcomes one of the most significant barriers to the development of practical quantum devices: the need for extreme cryogenic cooling. The object at the center of the experiment was a tiny cluster of three glass nanospheres, forming a structure with a diameter about ten times smaller than a human hair. While microscopic by everyday standards, this object is enormous from a quantum physicist's perspective, containing several hundred million atoms. To date, observing the subtle and fragile effects of quantum mechanics in objects larger than a few atoms has typically required cooling them to temperatures near absolute zero (-273°C). 

The Swiss team pioneered a novel method to bypass this requirement. Using a highly focused laser beam known as an "optical tweezer," they levitated the nanoparticle cluster inside a vacuum chamber, effectively isolating it from environmental vibrations and thermal interference. They then employed a sophisticated laser system to systematically extract energy specifically from the particle's rotational motion. This process effectively "froze" the particle's spin, suppressing the classical, heat-induced trembling to an unprecedented degree, all while the particle's core physical temperature remained at room temperature. 

The results of the experiment were record-breaking. The researchers achieved what they termed a "quantum purity" of 92%. This means that 92% of the object's residual motion was attributable to quantum zero-point fluctuations, the fundamental, inescapable jiggling that quantum mechanics predicts for any object, even at absolute zero, while only 8% stemmed from classical thermal motion. This level of purity is remarkable not only because it was achieved at room temperature but also because it surpasses the purity levels previously reached, even in state-of-the-art cryogenic experiments. The implications of this discovery are profound, as it dramatically lowers the barrier to entry for the development and deployment of quantum technologies, potentially accelerating the creation of advanced quantum sensors for navigation and medical diagnostics.  

Source: ETHZ News