eurier_br

>Quantum entanglement is different though than the classical case you describe. There is no classical correlation that is as strong as the quantum correlations. That's what Bell proved in his theorem: if you only have local interactions and assume that the two systems are correlated and actually already have the states really and we are simply ignorant of them, then the amount of correlation you get between the two systems is smaller than the amount of correlation that quantum mechanics predicts, and the amount verified by quantum experiments.

First of all, I kind agree with you. After all, the experimental observation of the violation of the Bell inequality is a landmark win for the probabilistic nature of quantum mechanics and it is undeniable. Also, the gloves example is just a particular case of "Bell's theorem experiment" with sensors aligned along the quantization axis of the conserved observable being measured (Measuring Sz in superposition of |+>z and |->z, for example).

Second, I used this example to simply say that "there can be correlations without the need to transfer information" at superluminal speeds. That is, entanglement either quantum or classical is not incompatible with general relativity nor non-local.

>I don't see what the measurement problem has to do with locality.

In the way I understand Bell's theorem (keeping statistical independence), it mainly tells us that i) if there is a hidden variables theory that explains QM results, it needs to be non-local. And, ii) if there is not a hidden variables theory, the state prior to the measurement is truly indetermined in the sense that we are not simply ignorant of the true state.

For me, ii) introduces non-locality in the sense that measuring one entangled particle will change the state of particle 2 irrespectively of time-space separation. You can say that there is no such a thing "state of particle 2" there is just the "entangled state". But this, in turn, invites the discussions of "physicness", "realness", etc of "states" and "wavefunctions". Which seem to be sidestepped due to the overwhelming success of the theory.

>The problem with measurement is more that it is non-unitary.

I am not aware of the consequences of this. If not too bothersome, could you discuss possible (EDIT: possible consequences that impact) experimental results of this? Thanks

I, personally (and a bunch of other physicists), think that the issue is not exactly the entanglement. If you take a pair of gloves and send each piece to two separate people, the moment either of them open the box they will know instantly which piece (left or right) the other got, because both of them knows that a pair of gloves comes with a right piece and a left piece. This is why entanglement doesn't violate general relativity, each person updates their knowledge instantaneously but there is no flow of information from one person to the other.

The true issue, according to some people (me, an experimental materials science-focused physicist, included), is the measurement problem. It updates the state of entangled systems instantaneously, including very space-separated systems. In this way the measurement is provokes the collapse of the quantum state in a non-local way. The problem is that the effects of measurement in quantum systems described by a postulate in quantum theory. So, in my opinion, the non-locality remains not explained and is generally neglected as a non-issue by the community at large.

From your list, European people would miss only Apple and Google. Considering EU is the second largest market for both I highly doubt they would willingly leave the region. Even if this was the case EU would throw all it could to create heir own silicon valley. As a brazilian living in Paris, I have a feeling people here would see the exit of some this companies wih almost pride.

Look to those error bars. It might be a great first work and give us some understanding but in no way it provides clear evidence. Even more when you factore in all the criteria for the pannel.