June 5, 2016

Is quantum thinking blocking roads to superdeterminism?

Gerard 't Hooft wants to make things simpler by thinking harder. He thinks Einstein might still have been right when he said that God does not throw dice. 'T Hooft dares to entertain the rather eccentric thought that the uncertainty inherent to quantum mechanics might actually not be a fundamental part of reality but could instead be an artifact that's only currently unpredictable because the theory is incomplete. He posits that the current formulation of quantum mechanics is statistical because it only offers a glimpse of something even deeper.

For many this claim will make their eyes roll because conventional wisdom is clear on the fact that the uncertainty principle is a key cornerstone on which quantum mechanics is built. You might rightfully ask whether we didn't already resolve this debate 80 years ago or if the seminal theorem developed by John Bell in the 60s and subsequent experiments didn't already close the door on local realism and hidden variables. After all, most Physicists are of the opinion that it has been conclusively demonstrated that entanglement can't be explained by any deeper level of physics. Still, even though the vast majority would respond with a definitive yes to being asked whether uncertainty is fundamental, there are some oddballs who will respond with "sort of" or worse, they might slap you in the face with "maybe", perhaps even "maybe not".

You might think the people who aren't certain about uncertainty would be crackpots with no degree whatsoever but actually... Although 't Hooft certainly is a crackpot ;), he also happens to have won a nobel prize in physics for his contribution in assembling the Standard Model of particle physics and he questions the conventional approach. In the past decade he has become more verbal in his opposition and continues to throw his weight behind the side that errs on cautions and prefers to go with "maybe".

Some excerpts from this brain wrecking interview;

"When I first chatted with ’t Hooft for an article eight years ago, he told me he wasn’t sure how to evade Bell’s reasoning. Since then, he has sought to jump through a loophole known as superdeterminism. It’s a weird and downright disturbing idea.

The sober way to put it is that physicists are never able to conduct a fully controlled experiment, since the experimental setup they choose is not strictly independent of the processes that created the particles. Even if the experimentalists live on Earth and the particles come from quasars billions of light-years away, they share a common past in the very early universe. Their subtle interdependence creates a selection bias, misleading physicists into thinking that no deeper level of physics could explain the particle coordination, when in fact it could.

The dramatic version is that free will is an illusion. I think you have to assume that Bob has made a decision not out of free will, but by some predetermined correlation. You can do the exercise. You can ask about a source emitting photons and the ancestors of Alice and Bob. While the source emits photons, Alice and Bob have not yet been born. They are many, many light-years away from each other. Those ancestors —the atoms in them— eventually cause Alice and Bob to make their decisions. Those atoms are correlated with the atoms of the source. Everything is correlated with everything else—not a little bit, but very, very strongly.

In quantum physics, there’s a notion of counterfactual measurement. You measure what happens if I put the polarizer this way, and then you ask, what if I had it that way? In my opinion, that is basically illegal. There’s only one thing you can measure.

Quantum mechanics is just a tool—and an extremely useful tool. That’s the way I think quantum mechanics has to be looked at. The theory is that you have something classical underlying quantum mechanics, obeying totally classical laws of nature except that ordinary classical theories are based on the real numbers. I’m not excluding real numbers as a good basis for a classical theory, but I’m also considering other options, such as the integers or, even better, numbers that form a finite set. I think I need finiteness at all levels of an ultimate theory.

This is motivated by Planckian discreteness. At the Planck scale, it’s likely that you only deal with Boolean variables and integers, because that’s what the holographic principle of black holes seems to be telling us—that the amount of information on the black hole horizon is actually finite."




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