Quantum reality is either weirdly different or it collapses

That means that if we rotate our apparatus so that we are measuring spin left and right, the result will be random—the electron will be either spin-left or spin-right with 50 percent probability.This is a relatively simple experiment to do, so Wigner grabs his friend, Alice, and places her in a sealed laboratory. When Wigner makes his measurement, hypothetically, he could end up with a result where Alice measured spin-down when in fact she measured spin-up.Two “facts” contradict each other, but both are based on reality. Wigner’s solution to this problem was that the quantum state cannot exist at the level of the observer: the superposition state must collapse before that occurs.The newly published extended version combines the original Wigner’s friend thought experiment with John Bell’s thought experiment (Bell’s thought experiment is old enough that it is now routinely tested in experimental physics). The measurement results reveal the correlations between the entangled pair, filtered by the wave function collapse of the two observers.What Wigner and Bell tell us about reality requires some thought. We have to accept some of the following possibilities: an observer's measurements are not necessarily real, reality is not local, super-determinism is real, or quantum mechanics ceases to function somewhere before macroscopic observers get involved.To extend on that last paragraph: the researchers' version of Wigner’s friend was not actually a macroscopic observer—it was a photon, which is an inherently quantum object.