When a singer belts out a tune while a guitar player strums along, sound waves travel through the air, driving collective oscillations of the molecules within. Meanwhile, at the quantum level, something similar is going on. Atoms inside materials, everything from our bodies to metals and more, naturally jiggle around, creating tiny vibrational waves that ripple across the material. These vibrations are known as phonons: the quantum version of sound waves.

Now, physicists at Caltech and Stanford University have developed devices called nanoelectromechanical systems (NEMS) that allow phonons to exhibit their quantum behavior purely through the intrinsic properties of the material that makes up the device.…