It starts out complaining that a Physics Nature article about Bell Tests was not completely precise. The Bell Tests prove that quantum mechanics experiments are inconsistent with local hidden variable theories.

As Bell and others have pointed out, there are some subtle assumptions: that the experimenter can make free choices (no superdeterminism), that future does not cause the past (no retrocausality), and that experiments have single outcomes (no many-worlds). All of these possibilities are crazy, and no serious person would believe in them. So these are reasonable assumptions.

If their only point was that a precise statement would mention these possibilities, that would be fine. But they go further.

They say that some people believe that they have the free will to do the measurements they choose, and then "It is, in hindsight, difficult to understand how this as- sociation came about." That is, they do not understand how people could think that they have the free will choose equipment settings.

Understanding the implications is even more important now that the experimentally observed violations of Bell’s inequality have been awarded the 2022 Nobel Prize in Physics. Contrary to what is of- ten stated, these observations do not demonstrate that “spooky action at a distance” is real and nature therefore non-local.The Nobel citation did not say that spooky action is real, or that there is anything wrong with quantum mechanics.

Rather, the observations show that if nature is local, then statistical independence must be violated. We should therefore look for independent experimental evidence that can distinguish the two different options: non-locality and statistical independence, or locality and violations of statistical independence.No, they are wrong here. The Bell observations show that if nature is local, then the theory must be a non-classical theory like quantum mechanics, or else we have one of the crazy loopholes like superdeterminism, retrocausality, or many-worlds. Saying non-classical is essentially the same as saying no local hidden variables.

Their deceptive title is "Bell's theorem allows local theories of quantum mechanics". That is completely correct statement, as local quantum mechanics is what all the textbooks teach. But what the body of the paper says is that Bell's theorem allows local superdeterminism, and that is the opposite of quantum mechanics. There is no superdeterministic theory of quantum mechanics.

Believing is superdeterminism is essentially a rejection of all science in the last millennium. So is retrocausality and many-worlds. You can believe in it if you want, but it is quite wrong to say that it is required by locality.

Dr. Bee has started expanding her podcasts to covering science news. She does a competent job, and she is very knowledgeable about Physics. But how can you trust anyone who believes that no one has any free will to do experiments, and that every randomized trial is fake?

Roger, there are deterministic accounts of QM using classical random fields that don't need signal nonlocality but natural nonlocal propagators. See Andrei Khrennikov and Peter W. Morgan. From my understanding, Bell experiments still employ a fair sampling assumption due to fluctuations, possibly sub-Planck. We don't account for the thermodynamics of the measuring device! You can violate Bell inequalities with classical light, Brownian motion (disappears at finer granularity), water waves (see recent Bell test with hydrodynamic analogs) and even simple "chaotic balls". Bell doesn't disprove determinism or locality but certainly deterministic particles. Since lambda can be psi, QM is nonlocal, unless you believe the wave function is psi-epistemic, in which case you are implying a deeper theory. I wouldn't simly reason backwards from a desire to have free will. Nature is what she is.

ReplyDelete"Since lambda can be psi, QM is nonlocal" -- No, that is wrong. Bell's theorem is about classical theories, not QM. It cannot say anything about whether QM is local or nonlocal.

ReplyDelete"unless you believe the wave function is psi-epistemic, in which case you are implying a deeper theory." -- I don't think it matters whether you interpret psi as epistemic, or believe in a deeper theory. That is just philosophy.

You're wrong. Bell's inequality is a statement of mathematics that you can describe with correlation polytopes and was discovered by Boole. Waves are "classical" but they escape Bell arguments if there are ANY fluctuations. Continuous signal theory suggests more sensitive detectors, such as Tungsten-based Superconducting Transition-Edge Sensors (W-TESs). Aspect and Co simply dismiss the importance of the loophole. It's not philosophy.

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