4 ms·
With respect I simply disagree with Feynman that the double slit experiment contains everything... Maybe in suggestive outline? As an example of how QM is weir
by crdrost 7y ago
With respect I simply disagree with Feynman that the double slit experiment contains everything... Maybe in suggestive outline?
As an example of how QM is weird, my go-to is a game that I call Betrayal. It is a challenge for a 3 person team. The teammates go through rounds where they are relativistically separated and unable to talk with each other; each such room has a big computer screen and two buttons labeled 0 and 1, and during each round each teammate has to press one or the other of these buttons; then their selections are summed up to a number that we call The Sum.
The reason we call this Betrayal is that we are trying to force one of the teammates to betray the other two. So 25% of the time we run a “control round” where we ask everyone to make The Sum even, and the team passes the round if The Sum is even. Or the rest of the time we secretly select one of the three at random to betray their colleagues: we tell the other two the true goal, make The Sum odd, and the team passes the round only if it is odd: but we lie to the traitor and tell them to make The Sum even, so they will work at cross purposes to the other two.
The key result is that there are 4 cases and classical strategies can only work for at most 3 of them, so your pass rate is limited to 75%. But quantum players who share a so-called “GHZ state” can pass 100% of trials in principle—albeit quantum computers have finite probabilities of simply failing, but if you could improve that to 90% fidelity then over the course of 100 rounds you will still score visibly ahead of the 75s, occasional 80s, and rare 85s produced by random chance.
The key is that quantum systems come out with these strange global correlations that cannot be explained classically. You also cannot see them locally; nobody knows the round succeeded until everyone comes back together to compare what bits everyone committed to.