I Why all the rejection of superdeterminism?

[ueit]

I was talking specifically about a stylized version of the EPR experiment, to show the role of superdeterminism as a loophole. I was not discussing how physics is supposed to work.
The point of using anthropomorphic language was because it makes the implausibility of superdeterminism clearer. In the EPR experiment, Alice can decide, ahead of time, to base her choice of which setting to use on absolutely anything--whether she sees a shooting star, the scores of the game on the radio, etc. She can make her decision as "anthropocentric" as she likes. In order for the superdeterministic loophole to make sense, the hidden mechanism has to anticipate her choice. So potentially it has to predict the future of the universe with unerring accuracy.

And, no, it is nothing like GR. Determinism and superdeterminism are not the same things. That's just a misconception on your part.

The same argument making "the implausibility of superdeterminism clearer" can be used to make any physical theory implausible, just in my example with GR. The Earth anticipates where the sun will be 8 minutes from now and accelerates toward that particular place (not where the Sun is seen with the eyes). The Sun needs to calculate where all the stars in the galaxy will be thousands of years from now to move so that it remains in the spiral arm, etc.

It is not the case that Alice makes a choice about how to set the detector and the source somehow anticipates her choice. The situation is like this:

The source of entangled particles is a quark/electron subsistem (S1)
Alice, her detector and whatever she decides do use to help her with the decision is another quark/electron subsistem (S2)
Bob, his detector and whatever he decides do use to help him with the decision is another quark/electron subsistem (S3)

S1, S2 and S3 form the whole experimental system, S.

As I have argued before, S1, S2 and S3 cannot be independent. In order to describe the evolution of S1, S2 and S3 you need the resultant electric/magnetic fields originating from the whole system, S. So, S1, S2 and S3 all evolve as a function of S. Given this situation, correlations are bound to appear between the motion of the subatomic particles of S1, S2 and S3. Sometimes those correlations could become visible at macroscopic level, and this is the fundamental cause for the observed correlations.

Now, why those exact correlations and not other? I don't know. As I have said one needs to perform a simulation of S and see what the result is. If the result is correct, the theory might be right. But even in this case you will not get a simple explanation in terms of an oversimplified macroscopic description.

Andrei

 

[stevendaryl]

There is a precise mathematical version of this: There is no algorithm that can tell whether an arbitrary given program stops for an arbitrary given input. But this theorem has not the slightest physical implications, since the universe is neither an algorithm nor a Turing machine.

Actually, what I'm talking about is not the same theorem. It is the theorem that it is impossible, in general to predict the future state of a program in a time less than the time required to just run the program. There is a universal program that can predict future states of other programs, but not in a timely manner. In contrast, there is no program that can solve the halting problem.

 

[A. Neumaier]

the claim that superdeterminism can reproduce the quantum predictions for EPR

I never made that claim.

The same argument shows the impossibility of the kind of superdeterminism required to make EPR-type predictions using a deterministic theory.

It is based on the assumption that the dynamics is effectively computable. This is a ridiculous assumption. Almost no deterministic dynamics is computable, and it need not be. Certainly Newton's theory of gravity is not computable.

 

[stevendaryl]

The same argument making "the implausibility of superdeterminism clearer" can be used to make any physical theory implausible, just in my example with GR. The Earth anticipates where the sun will be 8 minutes from now and accelerates toward that particular place (not where the Sun is seen with the eyes). The Sun needs to calculate where all the stars in the galaxy will be thousands of years from now to move so that it remains in the spiral arm, etc.

That shows exactly the difference between a deterministic theory and a superdeterministic theory. GR is deterministic, but not superdeterministic.

If instead of the sun and the Earth, you have a rock that is orbiting a massive spaceship at a distance of 8 light-minutes, far from any other gravitational sources, and that spaceship can maneuver using rockets, then it absolutely will not be the case that the acceleration of the rock will be toward where the rocket will be 8 minutes from now (or whatever the claim was). If the spaceship uses rockets to change locations suddenly, the behavior of the rock will continue as if the spaceship were still where it was until the information about its new location and velocity has time to reach the rock.

Thanks.

 

[stevendaryl]

I never made that claim.

Well, that's what this discussion is about.

 

[stevendaryl]

It is based on the assumption that the dynamics is effectively computable. This is a ridiculous assumption.

That's why the superdeterministic loophole can't actually work.

 

[ueit]

Yes, if we use deterministic field theory, then the whole universe evolves together. Show me how that leads to the quantum predictions for EPR. Actually, don't. Write a paper deriving the quantum predictions from a classical field theory. Then we can discuss it here. As it is, you're talking about a nonexistent, let alone mainstream theory.

I have already done that in a previous post:

Stochastic electrodynamics as a foundation for quantum mechanics
Physics Letters A - Volume 56, Issue 4, 5 April 1976, Pages 253-254

http://www.sciencedirect.com/science/article/pii/0375960176902978

The most up-to date version of the theory is published in a book. You can find it free here:

The Emerging Quantum
https://loloattractor.files.wordpre..._marc3ada_cetto_andrea_valdc3a9bookzz-org.pdf

It seems to me that while you are continuously asking me to present papers and so on you don't take seriously your burden of proof. For example you make the claim that in order to get EPR results in a deterministic theory you need the ridiculous mechanism with objects anticipating what other objects will do. I have seen no rigorous argument about that. None of the scientists working on superdeterministic theories, like 't Hooft and the autors of the book above have used such a model.

Andrei

 

[ueit]

That shows exactly the difference between a deterministic theory and a superdeterministic theory. GR is deterministic, but not superdeterministic.

If instead of the sun and the Earth, you have a rock that is orbiting a massive spaceship at a distance of 8 light-minutes, far from any other gravitational sources, and that spaceship can maneuver using rockets, then it absolutely will not be the case that the acceleration of the rock will be toward where the rocket will be 8 minutes from now (or whatever the claim was). If the spaceship uses rockets to change locations suddenly, the behavior of the rock will continue as if the spaceship were still where it was until the information about its new location and velocity has time to reach the rock.

Thanks.

Your example is irrelevant because it falls outside the scope of GR. The rockets are not systems described by GR.

This situation is completely different from the description of EPR in terms of subatomic particles because there is nothing there that is not inside the scope of QM (and of the candidate hidden variable theory).

 

[stevendaryl]

Your example is irrelevant because it falls outside the scope of GR. The rockets are not systems described by GR.

It illustrates why GR is not superdeterministic, just deterministic.

 

[stevendaryl]

This situation is completely different from the description of EPR in terms of subatomic particles because there is nothing there that is not inside the scope of QM (and of the candidate hidden variable theory).

But the same conclusion holds. It doesn't matter what forces describe subatomic particles. As long as behavior is complex enough to do things like computations, it is not predictable in enough detail to allow a superdeterministic explanation of EPR statistics.

 

[ueit]

But the same conclusion holds. It doesn't matter what forces describe subatomic particles. As long as behavior is complex enough to do things like computations, it is not predictable in enough detail to allow a superdeterministic explanation of EPR statistics.

This has nothing to do with complexity. Increasing the number of objects will never lead to deviations from physical laws. If you have more field sources the object moves just as easily in the resultant field (a classical superposition of the fields originating from each source in the case of electric field). It becomes harder to simulate on a computer but I fail to see the relevance of that.

Also, the predictability of the system is irrelevant because objects don't predict anything. The Earth moves towards the instantaneous position of the Sun because it so happens that the gravitational field points there. There is only an appearance of prediction.

The reason the rock cannot "anticipate" the rocket is that the rocket's engines are based on electromagnetism and not on gravity. For GR the rocket behaves like an unmoved mover and uncaused cause. GR does not expect the rocket to accelerate because there is no gravitational field responsible for that.

On the contrary, the human brain and everything else is made up of quantum particles. Nothing behaves as an unmoved mover in respect to them. The "sudden" decisions of a human are just late manifestations of the motion of charged particles in the brain. In EPR everything is like a planet, nothing is like a rocket.

 

[stevendaryl]

This has nothing to do with complexity.

Yes, it does. A complex enough system is unpredictable even if it is completely deterministic.

Look, publish your paper calculating EPR correlations using a superdeterministic theory. Then we can talk about it on Physics Forums.

 

[ueit]

It illustrates why GR is not superdeterministic, just deterministic.

GR is superdeterministic in regards to those systems described by it. If one can explain the behaviour of quantum particles in terms of micro black holes then again, there would be nothing outside of its scope.

It makes no sense to use a theory to describe a system outside its scope. That would amount to a falsification of the theory.

 

[ueit]

Yes, it does. A complex enough system is unpredictable even if it is completely deterministic.

Look, publish your paper calculating EPR correlations using a superdeterministic theory. Then we can talk about it on Physics Forums.

I have presented some papers. They are not written by me but since when is there such a requirement?

 

[stevendaryl]

I have presented some papers. They are not written by me but since when is there such a requirement?

Physics Forums is for the discussion of mainstream physics and refereed papers.

 

[ueit]

Physics Forums is for the discussion of mainstream physics and refereed papers.

OK, and I have presented such a paper:

Stochastic electrodynamics as a foundation for quantum mechanics
Physics Letters A - Volume 56, Issue 4, 5 April 1976, Pages 253-254

http://www.sciencedirect.com/science/article/pii/0375960176902978

It presents a theory along the lines I am arguing. Is Physics Letters A not good enough for you?

I also don't see the mainstream papers supporting your stance.

 

[stevendaryl]

OK, and I have presented such a paper:

Stochastic electrodynamics as a foundation for quantum mechanics
Physics Letters A - Volume 56, Issue 4, 5 April 1976, Pages 253-254

http://www.sciencedirect.com/science/article/pii/0375960176902978

It presents a theory along the lines I am arguing. Is Physics Letters A not good enough for you?

I can't read it without paying. It doesn't sound relevant, because you're talking about deterministic theories, while "stochastic" implies nondeterminism.

I also don't see the mainstream papers supporting your stance.

Bell is pretty mainstream.

 

[ueit]

I can't read it without paying. It doesn't sound relevant, because you're talking about deterministic theories, while "stochastic" implies nondeterminism.

The word stochastic is no important here. The theory is just classical electrodynamics with a primordial field added. This field plays the role of the vibrating oil bath in Couder's experiments. The field is described by Maxwell's theory so the theory is deterministic.

I have also presented a link to a book describing an updated version of the theory:

The Emerging Quantum
https://loloattractor.files.wordpre..._marc3ada_cetto_andrea_valdc3a9bookzz-org.pdf

This is not peer-reviewd although it is based on published articles and it is free. It has a whole chapter on entanglement.

Bell is pretty mainstream.

I don't remember Bell claiming that the appearance of correlations in a system described by a field theory requires the system to be simple enough to be computable or predictable or something of that sort. This seems to be your main argument against superdeterminism, and I am not convinced it is mainstream.

Also, in a continuous universe like ours you need infinite precision so even simple systems are not exactly computable.

 

[stevendaryl]

The word stochastic is no important here. The theory is just classical electrodynamics with a primordial field added. This field plays the role of the vibrating oil bath in Couder's experiments. The field is described by Maxwell's theory so the theory is deterministic.

I have also presented a link to a book describing an updated version of the theory:

The Emerging Quantum
https://loloattractor.files.wordpre..._marc3ada_cetto_andrea_valdc3a9bookzz-org.pdf

The issue being discussed is whether a deterministic local theory can reproduce the predictions of QM for the EPR experiment. That is not done in that paper. I don't see the relevance of that paper to this thread about superdeterminism.

 

[ueit]

The issue being discussed is whether a deterministic local theory can reproduce the predictions of QM for the EPR experiment. That is not done in that paper. I don't see the relevance of that paper to this thread about superdeterminism.

If a superdeterministic theory is shown to give the QM formalism (which is the claim of the paper) it will reproduce all predictions of QM, including EPR.

 

[stevendaryl]

If a superdeterministic theory is shown to give the QM formalism (which is the claim of the paper) it will reproduce all predictions of QM, including EPR.

It depends on what you mean by "giving the QM formalism". The standard "recipe" for QM has the following parts:

1. The system is described by a wave function, which is a square-integrable function on configuration space.
2. The system evolves according to Schrodinger's equation.
3. When a measurement is performed, the result is always an eigenvalue of the operator corresponding to the quantity being measured.
4. The probability of getting a particular eigenvalue is given by the square of the projection of the wave function onto the corresponding eigenstate.

The results of EPR don't follow just from Schrodinger's equation alone, but also the interpretation of measurements given by 3 & 4.

It's 3&4 that are not easily described by a deterministic local realistic theory. (Some would say it is impossible to describe them that way---as a matter of fact, there is a theorem to that effect.)

 

[stevendaryl]

It depends on what you mean by "giving the QM formalism". The standard "recipe" for QM has the following parts:

1. The system is described by a wave function, which is a square-integrable function on configuration space.
2. The system evolves according to Schrodinger's equation.
3. When a measurement is performed, the result is always an eigenvalue of the operator corresponding to the quantity being measured.
4. The probability of getting a particular eigenvalue is given by the square of the projection of the wave function onto the corresponding eigenstate

There is a little complication in rigorously discussing the EPR in these terms, because a couple of aspects of the experiment---no FTL interactions, the use of particle spin and/or photons--goes beyond nonrelativistic quantum mechanics.

 

[PeterDonis]

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