Direct observation of deterministic macroscopic entanglement

Quantum entanglement goes large occurs when two separate entities become strongly linked in a way that cannot be explained by classical physics; it is powerful resource quantum communication protocols and advanced technologies aim to exploit the enhanced capabilities of systems. To date, has generally been limited microscopic units such as pairs or multiples single ions, atoms, photons, so on. Kotler et al. Mercier de Lépinay demonstrate ability extend massive macroscopic systems (see Perspective Lau Clerk). Entanglement mechanical oscillators on length mass scale expected find widespread use both applications fundamental physics probe boundary between worlds. Science , this issue p. 622 625 ; see also 570