Experiments coupling light and sound reveal the surprising effect that measuring nothing can cool the vibrations of an object.

We use measurements to understand the world around us. With our eyes and ears, we constantly infer the state of our surroundings through the sights and sounds that reach us, allowing us to navigate our daily lives. While these “measurements” often focus on observing the presence of something, the absence of something also provides valuable information.

Researchers spanning Imperial College London, the University of Oxford, the University of Waterloo, the University of Leeds, and the University of Copenhagen have used the absence of scattered light to cool the motion of a tiny glass bead below room temperature.