Is spooky action at a distance real or does hidden variables exist? What does it mean in context of free will?

Question

I am complete amateur at this and research about physics is just a hobby for me. So with that in mind here is my problem:

I saw a few debates between physicists about spooky action at a distance vs hidden variables.

I also read that the Nobel prize in physics 2022 winner proved that there are no hidden variables at play in quantum mechanics. This is where Bell vs Einstein comes in. Bell stated that: violation of statistical independence = superdeterminism = no free will. Because of that Bell argued that there are only two possible options. Either the spooky action at a distance is real = free will is real = Bell is right. Or there are hidden variables = there is no free will = Einstein was right.

My question is: Who is right? Because I saw some physicist trying to disprove 2022 Nobel prize winner and because I don't understand physics deeply I don't know what to think of it.

Answer 1

First let me address some misconceptions:

• There were more than a single Nobel laureate in physics in 2022, there were three: John Clauser, Alain Aspect and Anton Zeilinger. Note that their first works were carried in the 70-80s, but Nobel recognition takes time.

• They showed experimentally (and sometimes even theoretically) that there are no local hidden variables. Emphasis on local here.

• The debates were between Albert Einstein (looking for deterministic mechanics) and Niels Bohr (arguing for probabilistic nature) in the 20-30s. John Bell came much later in the 60s.

• Free will in this context is a bad name. Some prefer free choice or statistical independence. It is not referring to voluntary free will (or whatever you find in the Bible) it is the idea that given two sources or detectors you should be able to reduce their correlations as much as possible (by disconnecting them, adding barriers or simply putting them far away from each other).

Now onto Einstein point:

Einstein wanted a deterministic theory that agreed with relativity. He argued that quantum mechanics was incomplete and that there should be "hidden variables" that determine what we measure. He came up with the idea that in order to violate Heisenberg uncertainty principle (that we cannot measure position and momentum with full certainty) we could use two entangled particles and measure position of one, momentum of the other and reduce the uncertainty of these values for both particles. This is called the EPR paradox. Under Einstein's perspective, if this is not possible, it would mean that measuring one particle is affecting the other, instantaneously.

Onto Bell:

It is impossible to describe Bell's point without math and lengthy paragraphs. I will just say that the experiments by the Nobel laureates showed that if one considers all the conditions that Einstein would have loved to keep (particles interact when close, have definite values and detectors are independent) then the experiments are violating those conditions. Which ones we cannot tell. Some of the following must be true:

• Particles do not have definite values previous to measurement (some kind of probabilistic nature). This was Bohr's point of view. Bell argued that this was not a solution.
• Particles can affect other particles without being close to each other (but entanglement cannot be used to send information or energy). This is often referred as quantum nonlocality. To my understanding this was Bell's choice.
• No free choice/statistical independence. We cannot uncorrelate detectors as much as we want, there is always some unusual correlation that enforces quantum results. (This is often called superdeterminism, because the correlations would have to be there since the Big Bang). Bell came up with this but it was not in favor of it.
• Retrocausality, some effects can travel back in time (but only those that do not violate special relativity).
• Some loopholes remain in the experiments. Most experts consider that the experiments of 2015 that tested multiple loopholes at the same time do not leave much room to error.

Answer 2

I will preface my answer by saying this seems like it'd be more appropriately asked on the philosophy stack exchange rather than here. However, I will give a brief response anyways.

On hidden variables vs. spooky action: By spooky action, I will assume you mean the probabilistic nature of quantum theory. Einstein favored determinism and therefore argued that the probabilities we observed weren't fundamental and instead were determined by deeper parameters that we could not or had not measured. Bell mathematically proved that any hidden variable theory is fundamentally incompatible with quantum theory. Since quantum theory is essentially the most successful scientific theory of all time, certainly much more so than any hidden variable theory, this proof basically discredits all hidden variable theories from consideration. i.e. nature is fundamentally probabilistic.

On free will: Often times, especially in philosophy, when a question is asked such that it proposes only 2 possible answers, there are answers not being considered (usually something like, both, neither, or a spectrum of sorts). In terms of giving you an answer, I will refrain from doing so and simply leave it at that, firstly because it doesn't quite make sense for this forum and secondly because it's not the kind of thing which has an agreed upon answer. I will however say, that while I don't believe in free will, I don't think it's a question that even matters. Either your choices are entirely your own or they're not, either way the choices are still made and they have the same consequences.