Using distant quasars, one of which emitted its light 7.8 billion years ago and the other 12.2 billion years ago, scientists have determined the measurements to be made on pairs of entangled photons. They found correlations among more than 30,000 pairs of photons.
Last year, physicists at MIT, the University of Vienna, and in other places provided strong support for quantum entanglement, the apparently bizarre idea that two particles, no matter how distant from each other in space and time, can be inextricably linked, in a way that defies the rules of classical physics. In a paper published in Physical Review Letters, the same team of researchers have made a comprehensive case for quantum entanglement and further constrained the options for the freedom-of-choice loophole.