Special Quantum Relativity: when you have 2 cats in boxes

Cats are like children, in that disorder increases geometrically by count.

Which is to say that Uncertainty is more uncertain than we had imagined.

(Daniela) Frauchiger and (Renato) Renner have a yet more sophisticated version (of Schrödinger’s Cat/Wigner’s observers). They have two Wigners, each doing an experiment on a physicist friend whom they keep in a box. One of the two friends (call her Alice) can toss a coin and—using her knowledge of quantum physics—prepare a quantum message to send to the other friend (call him Bob). Using his knowledge of quantum theory, Bob can detect Alice’s message and guess the result of her coin toss. When the two Wigners open their boxes, in some situations they can conclude with certainty which side the coin landed on, Renner says—but occasionally their conclusions are inconsistent. “One says, ‘I’m sure it’s tails,’ and the other one says, ‘I’m sure it’s heads,’” Renner says.

Some physicists are upset by the fact that separate observers do not always get the same measurements from a wave function collapse. Others are in the Haldane camp: “… stranger than we can imagine.”

If this is reality, it looks like theorists have a lot more work to do understanding and modeling it.