Room-Temperature Quantum Motion Observed in Levitated Nanoparticles Marks Major Step for Quantum Sensors

A research team from ETH Zurich has achieved a major breakthrough in quantum sensing by observing quantum vibrations in levitated glass nanospheres at room temperature. The experiment provides a key foundation for developing next-generation, ultra-precise quantum sensors.

Using advanced optical tweezer technology, the researchers suspended three glass nanospheres—each just one-tenth the width of a human hair—in a vacuum. By carefully manipulating polarized laser fields, they counteracted gravity and minimized external disturbances. Remarkably, the nanoparticles displayed clear quantum behavior: their minute rotational oscillations reached frequencies of over one million times per second, with amplitudes of only a few thousandths of a degree, confirming the quantum mechanical prediction of “zero-point fluctuations.”

Measurements showed a quantum purity of 92%, meaning that nearly all of the observed motion stemmed from quantum effects. This marks the first time that precise quantum measurements of micron-scale objects have been achieved at room temperature—without the need for ultra-cold environments typically required in quantum experiments.

Unlike most quantum studies that focus on single atoms or small molecules, these nanospheres consist of hundreds of millions of atoms, offering a unique platform to explore quantum behavior in macroscopic systems. Their larger size also enhances their potential for practical use in emerging quantum technologies.

This achievement opens new pathways for applied quantum science. High-purity quantum systems like this could help probe the connection between gravity and quantum mechanics, or enable the creation of ultra-sensitive sensors capable of detecting trace gases or subatomic particles. In the longer term, such technologies may revolutionize medical imaging, extract faint signals from noisy environments, or even power navigation systems that operate independently of satellites.