Entanglement is the strange quantum phenomenon in which two or more particles become so deeply linked that they share the same existence.
That leads to some counterintuitive effects, in particular, when two entangled particles become widely separated. When that happens, a measurement on one immediately influences the other, regardless of the distance between them. This “spooky-action-at-a-distance” has profound implications about the nature of reality but a clear understanding of it still eludes physicists.
Today, they have something else to puzzle over. Jay Olson and Timothy Ralph at the University of Queensland in Australia say they’ve discovered a new type of entanglement that extends, not through space, but through time.