B Is there any practical proof that quantum entanglement really works?

[Vanadium 50]

Suppose there is a new law: if measuring spin +1, then Biden will be president, otherwise Trump... you instantly know that Biden won. So you got information about who became president faster than speed of light.

Supposed there is a new law passed that on election day a box is opened. If it contains a left shoe, Biden is elected and if it contains a right shoe, Trump is elected. The mating shoe is placed in another box and sent far away. When it is opened, the people who opened it instantly know the results of the selection faster than the speed of light.

This should make it clear that what you wrote has nothing whatever to do with quantum mechanics.

 

[berkeman]

Doh-dee-ohh-doh...

 

[Nugatory]

Is there an experiment confirming that correlations work on really large distances such as from here to other stars?

The best experiments so far have been done across thousands of kilometers.

It’s hard to see how we could do such an experiment at interstellar distances, both because of the practical difficulties in setting up two detectors light-years apart and because we would need at least one of the particles to traverse that enormous distance without blundering into something (stray grain of dust, random molecule floating around, cosmic ray particle, ….) which would break the entanglement.

However, nothing in our current physics says that quantum mechanics wouldn’t work as expected if we could overcome these practical difficulties in an experiment. We might imagine theories that aren’t quantum mechanics and agree with QM at planetary scale but predict different results at interstellar scale - but with neither a candidate theory nor experimental evidence suggesting that QM is wrong this is a completely sterile exercise.