‘Levitating’ nanoparticles could push the limits of quantum entanglement

Physicists have suspended tiny glass spheres in a vacuum and made them interact with one another at close distance. The ‘levitating’ nanoparticles can be manipulated with exquisite precision, offering the tantalising prospect of probing quantum physics at a macroscopic scale. For example, if the particles can be slowed to their quantum ground state (as cold as they can get), it could become possible to put them into a state of quantum entanglement, meaning that some of their measurable properties — in this case, their positions — are more strongly correlated than would be allowed by the laws of classical, non-quantum physics.