A pair of diamond crystals, large enough to be seen by the naked eye, have been linked together by quantum entanglement. The diamonds are entangled such that manipulating one affects the other, even though they are physically separated. In this case, the crystals were 3 millimeters wide and 15 centimeters apart. (One of the diamond wafers is pictured below.) Indeed, Einstein called this phenomenon "spooky action at a distance," and scientists still don't understand how it's possible. The University of Oxford physicists published their work today in the journal Science. From Nature:
A vibration in the crystals could not be meaningfully assigned to one or other of them: both crystals were simultaneously vibrating and not vibrating.
Quantum entanglement — interdependence of quantum states between particles not in physical contact — has been well established between quantum particles such as atoms at ultra-cold temperatures. But like most quantum effects, it doesn't tend to survive either at room temperature or in objects large enough to see with the naked eye.
A team led by Ian Walmsley, a physicist at the University of Oxford, UK, found a way to overcome both those limitations, demonstrating that the weird consequences of quantum theory apply at large scales as well as at very small ones.