Reading a Something Awful thread about physics. Kind of lackluster overall, but it has this nice explanation of the no-communication theorem (says that you can’t transmit information faster than light via quantum entanglement):
Here’s a simplified setup: you have two (hypothetical) quantum “coins” that are entangled, brought far apart, and flipped. If coin A flips heads, B will always flip tails, and vice versa. This is repeated a bunch of times. So Alice takes coins A and Bob takes coins B and they do the experiment. If Alice flips her coin, Bob’s will be then determined to be the other side with 100% probability. If she doesn’t, Bob’s coin is 50/50. But either way, without comparing notes, Bob won’t notice any difference because his coin is 50/50 either way, either “naturally” when Alice doesn’t interfere, or through the entanglement because Alice’s coin is also 50/50. The key point is that any patterns that may arise are not apparent until both experiments communicate with one another at the speed of light or slower. Then Alice and Bob can look at the data and say, “Ah, my flipping of coin A must have caused coin B to behave in this way,” but you can’t actually tell that it did so without some other subluminal communication between Alice and Bob.
So thanks for that, DontMockMySmock.