Chinese Physicists Measure Speed of "Spooky Action At a Distance"

Einstein railed against the possibility of spooky action at a distance because it violates relativity. Now Chinese physicists have clocked it travelling more than four orders of magnitude faster than light

One of the strangest concepts in quantum mechanics is the notion of entanglement. This is the idea that two quantum particles can be so deeply linked that they share the same existence. When that happens, a measurement on one immediately influences the other, regardless of the distance between them.

This “spooky action at a distance”, as Einstein called it, has puzzled and fascinated physicists since it was first discussed in the 1930s. Einstein initially used it as evidence of the failure of quantum mechanics since this instantaneous action clearly seemed to violate relativity.