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Does superdeterminism save quantum mechanics?

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Re: Does superdeterminism save quantum mechanics?

#41

Post by naasking »

myridium wrote: post #29
quantum_mcts wrote: post #18

I'm from the many-worlds interpretation camp, and this "superdeterminism" business always strikes me as ironic. Proponents of hidden variables, in their desire to explain QM effects, arrived at the idea that there is something that permeates the Universe since the Big Bang and participates in every physical interaction. Existence of this something cannot be directly proven - since we are "inside" of it. How about the…

Totally agree. It's therapeutic to read this. Last I checked, many-worlds is a consequence of current quantum theory, not a postulate or additional axiom. Yet people treat it like such. Probably because it's 'spooky'. Then indeed it's ironic that they search for alternative explanations which try to say the same thing as many worlds but without saying 'many worlds'.

> Last I checked, many-worlds is a consequence of current quantum theory, not a postulate or additional axiom.

There is an additional postulate, namely that the state vector is the real world we inhabit. This may seem obvious to you and not amount to postulating much or anything with any substance, but that's a philosophical claim that isn't suggested by the physics.

There are also the problems of deriving the Born rule from the existing postulates of MWI. Last I checked, the existing derivations are not fully satisfactory to most physicists.

Re: Does superdeterminism save quantum mechanics?

#42

Post by naasking »

myridium wrote: post #38
naasking wrote: post #24

Earlier quoted context omitted.

I think that's more or less correct. GR suggests "time" isn't independent, we instead have 4-dimensional "spacetime". The idea that future inputs can influence past configurations can be perfectly sensible in this context. It's like a restricted form of consistent closed timelike curves. There was some development in this direction years ago: The Logic of Quantum Mechanics Derived from Classical General Relativity, h…

Why is GR required? Already in standard QFT (Minkowski metric; flat spacetime; special relativity) the propagator 'violates causality'. Although that phrasing is misleading; it doesn't mean there's any logical inconsistency. 'The future affects the past' you might say. Yes, well, all information about the future is derivable from information about the present. So actually those 'future influences' are determined by t…

Maybe GR isn't required. It seems like the simplest path to understanding how this could work for those who aren't familiar with QM though.

Re: Does superdeterminism save quantum mechanics?

#43

Post by rafaelero »

myridium wrote: post #40
rafaelero wrote: post #36

This is the first time I've read some way of looking at quantum physics that actually make sense. I hope it is indeed correct and all those ~smart people who were putting their ridiculously complex theory of quantum physics at our throats end up being ridiculed.

You're exactly the target audience for her content :) .

I suppose. It does seem pretty logical that statistical independence between measurement and particles could be violated, and I am just a newbie. If someone could explain why people overlooked this fact I would be very interested.

Re: Does superdeterminism save quantum mechanics?

#45

Post by sigmoid10 »

rafaelero wrote: post #36

This is the first time I've read some way of looking at quantum physics that actually make sense. I hope it is indeed correct and all those ~smart people who were putting their ridiculously complex theory of quantum physics at our throats end up being ridiculed.

This reminds me of Feynman's famous quote: "If you think you understand quantum mechanics then you don't understand quantum mechanics." Frankly, I'm baffled how some scientists still clinge to classical physics and absolute determinism, just because they describe our macroscopic world nicely. People have tried to argue against quantum principles 100 years ago and some still do it today, even going so far as to believe that the entire universe conspires against us since the big bang (which is what supetdeterminism boils down to in light of things like entanglement) rather than accept the inconvenient truth: our universe is much stranger than classical physicists could have envisioned.

Re: Does superdeterminism save quantum mechanics?

#46

Post by slavik81 »

naasking wrote: post #37
akvadrako wrote: post #15

Earlier quoted context omitted.

> Superdeterminism, arguably misnamed, simply argues that QM is deterministic, where Bell and others have argued it is not. No, this is completely wrong. Super-determinism is more than determinism. Super-determinism is about conspiratorial coincidences – so the measurement settings you choose just happen to be the ones which will make it look like the world is quantum. Other quantum interpretations are also determini…

Many worlds is not deterministic in the sense that the experimenter cannot predict in which world they will end up. Pilot wave theory is deterministic, but non-locality is retrocausal influence under GR. I also don't think your take on superdeterminism is entirely correct. As Sabine says, "statistical independence" is the "no superdeterminism" assumption, and some superdeterministic theories can be conspiratorial, bu…

> Many worlds is not deterministic in the sense that the experimenter cannot predict in which world they will end up.

It is deterministic. The experimenter ends up in all of them.

Re: Does superdeterminism save quantum mechanics?

#47

Post by geertj »

myridium wrote: post #25

Quoted post unavailable.

Honest question, why did you have to go ad hominem? If you look at her papers she’s obviously well versed in QFT and GR. You may disagree with her philosophical views but making the case that she doesn’t understand QM doesn’t pass the smell test.

Re: Does superdeterminism save quantum mechanics?

#48

Post by coderenegade »

graycat wrote: post #13
PeterWhittaker wrote: post #8

Earlier quoted context omitted.

In the context of Bell’s Theorem, statistical independence is understood to mean that, if extant, hidden variables are not correlated with how measurements are being performed. Bell’s Theorem is only correct if this assumption holds. Hossenfelder is arguing that the assumption is incorrect: that Bell’s Theorem is incorrect precisely because there ARE hidden variables and that these ARE correlated with measurement set…

At least for now, I'm willing to f'get about issues of "free will". Thanks, I will keep trying to make sense out of Bell's work. I keep getting stuck trying to read quantum mechanics: One place was the claim that the wave functions form a Hilbert space. Nope: As I read in W. Rudin, Real and Complex Analysis , a Hilbert space is a complete inner product space where complete means that every Cauchy convergent sequence…

You might be interested in some code that illustrates the problem of hidden variables and the EPR paradox: https://pastebin.com/J4ZUhG8e. The issue is that we can't replicate what QM predicts (and experiments validate) using hidden variables without additional steps or assumptions. For example, in that code, there are a few possible ways we could still produce the QM correlation function with local hidden variables:

1. When we measure the first particle, we alter the second particle to produce the desired correlation. This is the communication loophole. If you move the particles far enough apart, it requires superluminal communication, which GR says is impossible. This is what Einstein was getting at in the EPR paper; if what the Copenhagen interpretation of QM says is true, and the particle is in both states at once, measuring it collapses it to a given state, and the other particle suddenly "knows" what it should be, even though the propagation of information through the universe has a speed limit.

2. We could define an additional hidden variable in [0,1], and do rejection sampling at the detector. Anything that is rejected is not detected, and we only deal with detected particles. This is the detection loophole. I'm not an expert, but this is the only one that really makes sense to me as a good candidate for a hidden variables theory, and I believe it's been ruled out by experiment.

3. We could bias the initial sampling of our hidden variables. The problem is, this requires that we know the setting of the detector ahead of time. As far as I understand it, this is essentially what superdeterminism comes down to: you know the experiment setting ahead of time because everything is completely deterministic, like a movie reel being rolled forwards. You can thus bias the initial sampling step to produce the QM correlation function. Aside from being unfalsifiable, it still leaves open the question of why this would happen. It essentially means that all QM experiments have predetermined outcomes, and for whatever reason, those outcomes are the outcomes we observe.

Ultimately, it seems to me that Bell's inequality is more a statement about the fundamental incompatibility of quantum probability with classical mechanics and probability. If QM is correct, and it seems that it is, then you have to give up certain assumptions such as locality.

Re: Does superdeterminism save quantum mechanics?

#49

Post by lmm »

astrange wrote: post #17
midjji wrote: post #11

Earlier quoted context omitted.

Just means she hasn't thought of the inevitable consequences. Besides, the paradox she is resolving isn't a paradox, she just does not understand the answer in standard QM.

Seems like if you “thought of the consequences” and “understood QM” here you’d have a theory of everything all ready to go.

I do, it's called "quantum mechanics". It's the most thoroughly verified theory in the history of physics, and in my subjective opinion the most mathematically beautiful one. It is the greatest pinnacle of human scientific achievement.

But people think the idea that things might superimpose on each other like waves is weird, it's not what they see everyday objects that are 10,000,000,000x larger behaving, so it can't possibly be right, and they keep making up overcomplicated nonsense so that they can keep pretending that elementary particles behave like billiard balls.

Re: Does superdeterminism save quantum mechanics?

#50

Post by bryan0 »

myridium wrote: post #32
PeterWhittaker wrote: post #8

Earlier quoted context omitted.

In the context of Bell’s Theorem, statistical independence is understood to mean that, if extant, hidden variables are not correlated with how measurements are being performed. Bell’s Theorem is only correct if this assumption holds. Hossenfelder is arguing that the assumption is incorrect: that Bell’s Theorem is incorrect precisely because there ARE hidden variables and that these ARE correlated with measurement set…

> Superdeterminism, arguably misnamed, simply argues that QM is deterministic This is incorrect. QM is already deterministic. Where oh where do people get the idea that it is not?

The born rule for starters.
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