At a Glance
- Researchers at ETH Zurich used lasers to cool a levitated nanoparticle cluster to its quantum ground state, a feat typically requiring extreme cryogenic temperatures for comparable systems.
- By suppressing classical motion, the team observed the object’s fundamental quantum trembling with unprecedented precision, achieving a quantum state purity of 92 percent in the process.
- This breakthrough was accomplished entirely at room temperature, establishing a more cost-effective and energy-efficient platform for creating high-purity quantum systems than traditional deep-freeze cooling methods.
- Published in Nature Physics, the work demonstrates exceptional control over an object containing hundreds of millions of atoms, effectively bridging the gap between classical and quantum scales.
- This highly controllable system paves the way for developing advanced quantum sensors to search for dark matter, improve navigation, and create new medical imaging technologies.
Researchers at ETH Zurich have achieved a significant breakthrough in quantum physics by cooling a levitated nanoparticle to its quantum ground state at room temperature. The team used laser beams to nearly halt the motion of a tiny glass cluster, achieving a record-breaking purity of 92% in the quantum state. This accomplishment, detailed in the journal Nature Physics, sidesteps the need for costly and complex cryogenic cooling, thereby opening new avenues for the development of advanced quantum technologies.
The experiment involved a cluster of three silica nanospheres, collectively smaller than the width of a human hair, levitated in a vacuum using an optical tweezer. This device uses a focused laser to trap and hold the particle. While this setup counteracts gravity, the nanoparticle still exhibits a tiny, rapid trembling motion known as zero-point fluctuation, a fundamental prediction of quantum mechanics stating that no object can be perfectly still. By using a technique called coherent scattering, the researchers effectively cooled this specific rotational motion, reducing its energy to the lowest possible quantum level.
This achievement is remarkable for two reasons: it was performed at room temperature, and it resulted in the highest quantum purity ever observed in a mechanical oscillator of its kind. Traditionally, reaching such quantum states required cooling objects to near absolute zero. The ETH Zurich team’s method is more efficient, prompting researcher Martin Frimmer to compare it to building a vehicle that “transports more cargo than traditional lorries and at the same time consumes less fuel” in an institutional press release. This level of control over an object containing hundreds of millions of atoms represents a major step in bridging the gap between the everyday world and the quantum realm.
The success of this experiment provides, in the researchers’ words, “a perfect start” for future applications. By creating a cost-effective and highly pure quantum system, the team has established a powerful platform for fundamental physics research, including the exploration of the relationship between gravity and quantum mechanics. It could also lead to the development of highly sensitive quantum sensors capable of detecting minuscule forces, which could aid in the search for dark matter, improve vehicle navigation systems without GPS, and advance medical imaging technologies.
References
- Dania, L., Kremer, O. S., Piotrowski, J., Candoli, D., Vijayan, J., Romero-Isart, O., Gonzalez-Ballestero, C., Novotny, L., & Frimmer, M. (2025). High-purity quantum optomechanics at room temperature. Nature Physics. https://doi.org/10.1038/s41567-025-02976-9
- E. T. H. Zurich. (2025, August 6). New work achieves a pure quantum state without the need for cooling. Phys.Org; E. T. H. Zurich. https://phys.org/news/2025-08-pure-quantum-state-cooling.html
