Is there a fundamental flaw in our understanding of space and conservation laws?

[ttn]

I know I said I wasn't going to comment any more on this thread (god, I think I might have actually said that twice already ) but I can't pass this up because it makes everything so clear:

In order to describe Aspect’s experiments I only need information regarding the state of the two detectors, few fractions of a second before detection and nothing else.

That is simply not true. If you think that, you haven't sufficiently understood Bell's theorem and/or the superdeterminism you are proposing.

If you consider as "given" (relative to ascribing probabilities for the possible outcomes of the nearby measurement) only (a) the state of the particle pair to be measured and (b) information regarding the state of the nearby detector, then you cannot account for Bell-inequality-violating correlations. That's the theorem. On the other hand, if, as I think your statement above is meant to imply, you consider as "given" the above (a) and (b) and in addition "information regarding" the state of the other, distant detector, then your account of the correlations is not local. *Obviously* you can "describe Aspect's experiments (i.e., account for the outcomes) if you allow each outcome to depend on the particle pair state and "information regarding the state of the two detectors, few fractions of a second before detection". But this would not be a *local* explanation of the outcomes, which is supposed to be the whole point, right?

So it is not an appeal to emotion, or some pointless rhetorical distraction, that I bring up all the stuff about billions of years ago and billions of light years away. This is actually what your theory *requires* us to consider if we are going to convert what you say above into an actual *local* explanation of the correlations. It is not good enough to say that the current settings of the apparatus "just happen" to be so as to fool us into thinking we have performed a non-biased measurement of the correlations. You must shoulder the burden of explaining how this (apparent) conspiracy could have come about, and the *only* way to do this *locally* is to search in the distant past for events which have *caused* (*locally*) the two settings and the particle state to get appropriately correlated. So, good luck with that.

My good friend and philosophical partner-in-arms vanesch will have to take up any further discussion of this on my behalf because this time I'm serious when I say I won't comment anymore! (Unless I change my mind...)

 

[vanesch]

Any deterministic theory requires, in order for a good prediction, a good knowledge of the initial parameters. If you choose to introduce as a parameter the properties of a photon generated at the big-bang then you find yourself forced to introduce the big-bang in calculations. The absurdity comes not from the theory but from the physicist who decided to use a practically unknowable parameter in his experiment

The point is that it is not very difficult to set into action an experiment that uses almost ANY kind of measurement to decide upon the settings of the polarizers. This can range from cosmic microwave background noise, to stuff happening in the brain of an experimenter, to sampling a song of the 1930ies... you can pick MIRIADS of ways to select the polariser settings, based upon totally different kinds of physical systems, and ALL of them have to agree upon the RIGHT polarizer settings in order to generate the right EPR correlations. That is, if we use samples of a song of Vera Lynn to decide upon the polarizer settings, then these samples have to be in agreement with the polarisations of the sent pairs of light pulses so as to generate EPR correlations. But we could decide in the middle of the experiment, to switch to CMB radiation noise as a decider for the polarizations, and this should simply continue. Etc...
In other words, all these totally different physical quantities have to be in agreement to generate the correct polarizer settings in agreement with the pairs sent out.

In order to describe Aspect’s experiments I only need information regarding the state of the two detectors, few fractions of a second before detection and nothing else.

The point is that that "information" can be Vera Lynn's song, or the CMB radiation or whatever, and this all has to come out correctly.

My analogy with the “gravitational EPR” gedankenexperiment shows how lame ttn’s “argument” is.

Not really. In the gravitational EPR experiment you propose, everything is a simple gravitational interaction. Your example doesn't work anymore if there is one single electromagnetic phenomenon happening, which "helps align" the stars. It is clear that if a gravitational EPR experimenter had the impression of having some freedom to align or not, the stars in the galaxy, that the argument wouldn't hold anymore - even if this freedom is only apparent. It simply means that the experimenter has some "way of deciding" to his disposal to align, or not, the stars in the galaxy, which means essentially that the experiment can be set up in such a way that alignment or not of the galaxies can be correlated with just any other phenomenon.


I agree with this but there is no need to misrepresent or exaggerate in order to close that argument.[/QUOTE]

 

[ueit]

I know I said I wasn't going to comment any more on this thread (god, I think I might have actually said that twice already ) but I can't pass this up because it makes everything so clear:

In order to describe Aspect’s experiments I only need information regarding the state of the two detectors, few fractions of a second before detection and nothing else.

That is simply not true. If you think that, you haven't sufficiently understood Bell's theorem and/or the superdeterminism you are proposing.

If you consider as "given" (relative to ascribing probabilities for the possible outcomes of the nearby measurement) only (a) the state of the particle pair to be measured and (b) information regarding the state of the nearby detector, then you cannot account for Bell-inequality-violating correlations. That's the theorem. On the other hand, if, as I think your statement above is meant to imply, you consider as "given" the above (a) and (b) and in addition "information regarding" the state of the other, distant detector, then your account of the correlations is not local. *Obviously* you can "describe Aspect's experiments (i.e., account for the outcomes) if you allow each outcome to depend on the particle pair state and "information regarding the state of the two detectors, few fractions of a second before detection". But this would not be a *local* explanation of the outcomes, which is supposed to be the whole point, right?

Bell's theorem proves that the properties of entangled particles and detectors' orientation are not statistically independent parameters. The theorem is silent about the mechanism by which the correlations are realized. It doesn't require it to be non-local.
Aspect's experiment used a fast-switching device to set the detector while the particles were in flight. Does the experimental result rule out a local mechanism behind the correlations? Not at all.

As I said, few fractions of a second before detection (the time it takes the photon to travel from the source to the detectors), just before the entangled photons are released, the information regarding the detector's state arrives at the source. Because I propose a local mechanism, that information is not "up to date" but this is not a problem. We've agreed that the detectors are deterministic systems, therefore knowing their state at a certain time is enough to predict their state in the future. So, when the particles leave the source they "know" how they will be detected even if they only have old information.

To better illustrate my point, let's say some aliens set up an EPR-type experiment. The source is placed on Earth and the detectors about 1 parsec away.
But the humans found out about the experiment and wanted to make fun of the aliens by sending them a message encoded in the experimental data. But, they don't know how the aliens will perform the measurements so what to do? Well someone comes with the idea of building a telescope so powerful that it can see the electrons and quarks the detectors are made of. He then puts the data into a computer and calculates the detectors' state one year into the future, when the measurement will be performed. It doesn't matter how the aliens will do to "chose" the detectors' orientation. A quick "scan" of their brain will inform humans about the so-called choice.

In conclusion, as I said before, there is no need for a non-local mechanism if the detectors are predictable and if their state (even if an old one, it doesn't matter) can reach the source via EM or other signals traveling at or bellow the speed of light.

Of course, finding the exact mechanism could be a difficult task, perhaps more dificult than going from Newtonian gravity to GR, but the fact that such an mechanism is allowed by Bell's theorem and all experiments performed to date is quite important.

 

[ueit]

The point is that it is not very difficult to set into action an experiment that uses almost ANY kind of measurement to decide upon the settings of the polarizers. This can range from cosmic microwave background noise, to stuff happening in the brain of an experimenter, to sampling a song of the 1930ies... you can pick MIRIADS of ways to select the polariser settings, based upon totally different kinds of physical systems, and ALL of them have to agree upon the RIGHT polarizer settings in order to generate the right EPR correlations. That is, if we use samples of a song of Vera Lynn to decide upon the polarizer settings, then these samples have to be in agreement with the polarisations of the sent pairs of light pulses so as to generate EPR correlations. But we could decide in the middle of the experiment, to switch to CMB radiation noise as a decider for the polarizations, and this should simply continue. Etc...
In other words, all these totally different physical quantities have to be in agreement to generate the correct polarizer settings in agreement with the pairs sent out.

The point is that that "information" can be Vera Lynn's song, or the CMB radiation or whatever, and this all has to come out correctly.

The key issue here is that those "totally different physical quantities" are not as different as you claim they are. If, at the bottom, all particles follow deterministic trajectories and if they can "communicate" their state via a local mechanism, similar to gravity in GR, it doesn't matter how complex or big a system is or what internal distribution it has. A button-pressing monkey or a computer analyzing "Vera Lynn's song" are, after all both quark-electron systems and I see no reason to look for different physical laws to describe each of them.

Not really. In the gravitational EPR experiment you propose, everything is a simple gravitational interaction. Your example doesn't work anymore if there is one single electromagnetic phenomenon happening, which "helps align" the stars. It is clear that if a gravitational EPR experimenter had the impression of having some freedom to align or not, the stars in the galaxy, that the argument wouldn't hold anymore - even if this freedom is only apparent. It simply means that the experimenter has some "way of deciding" to his disposal to align, or not, the stars in the galaxy, which means essentially that the experiment can be set up in such a way that alignment or not of the galaxies can be correlated with just any other phenomenon.

Sure, in my example, you can appeal to EM to "fool" gravity. But how can you propose to "fool" an electron or a quark if it follows a deterministic trajectory? You should use something else that is not "covered" by QM, a different kind of force. I don't have any idea of what that may be.

So, if you are limited to what QM (or better QFT) describes, and if the theory is deterministic you are like an astronaut, without any propulsion system, orbiting some planet. He might believe that it goes round and round because of his "free will" but he can do nothing but "choose" to follow that trajectory.

 

[reilly]

This for example:
http://arxiv.org/abs/quant-ph/0406173
Or this:
http://arxiv.org/abs/hep-th/0407228
http://arxiv.org/abs/hep-th/0601027
Or this:
http://arxiv.org/abs/gr-qc/0611037

Interesting work indeed. But where does it go? Theory is nice, particularly when it is close to experiment. I first enountered Bohm's work some 50 years ago. It's still outside the mainstream, beause it has contributed little or nothing to further any branch of physics that's connected to experiments. My sense is that the arguments about Bohm have not changed much over the last 50 years.

Regards,
Reilly Atkinson

 

[reilly]

Now, whether this is "really true" or not doesn't matter for me: I just imagine that what the standard QM formalism tells me, is somehow "what really happens physically" in my mind's eye. As such, I don't have to fiddle with the formalism to get my picture up and running, within that picture, I don't wonder how there is "action at a distance" in EPR, or if there is some backward causal magic in delayed choice quantum erasers.

If this doesn't work for others, then they will have to devise their own way of getting - if they desire so - a different way of understanding quantum theory. I just want to be of some help for those who struggle with things I also struggled with (and many do), and for which I found "ease of mind" with MWI. As I repeated often, to me, MWI is just a way of getting a "feel" for quantum theory as it is now. It is not some credo of some weird religion.



I agree with that. That's why I insist on letting the formalism (which has been build upon observation) guide the interpretation, and not vice versa.

Sounds good to me. I find MWI confusing, and take my Born interpretation with a grain of salt.

I think about an imaginary QM world based largely on a three-point interactions, transitions if you will. I think sometimes pictures of such are called Feynman Diagrams. Like many,I think the standard diagrams are a God send. But, it would be a great stretch to say they represent real processes -- but then many don't

Regards,
reilly

 

[vanesch]

The key issue here is that those "totally different physical quantities" are not as different as you claim they are. If, at the bottom, all particles follow deterministic trajectories and if they can "communicate" their state via a local mechanism, similar to gravity in GR, it doesn't matter how complex or big a system is or what internal distribution it has. A button-pressing monkey or a computer analyzing "Vera Lynn's song" are, after all both quark-electron systems and I see no reason to look for different physical laws to describe each of them.

Yes, but look at the following. We have the impression that we can "decide" about the settings of the polarizers. This means that we can essentially correlate this with almost any other phenomenon. Now, I don't want to drift in a discussion here about "free will" - I can accept that free will is an illusion in a deterministic universe, but nevertheless, it has a meaning. The meaning is that the choices can be based upon "arbitrary" correlations (human brain states, photons coming from the back end of the universe, samples of songs sung long ago...). We have learned somehow, throughout the entire evolution of science (and even before that), that when things seem to depend upon "free will" that they are statistically independent. In fact, the whole endeveour of science is based upon that idea! "Controlled experiments" are nothing else but exactly that: we change "arbitrarily" some parameters while keeping others constant, and we deduce "causal relations" from that. You push arbitrarily the button, and you see the light go on. You do that 50 times, and you conclude that there is some causal relationship between you pushing the button as cause, and the light going on as consequence... maybe due to the current that will flow in the wire, or maybe for another reason. In fact, THE WHOLE OF SCIENCE (and all of our common sense knowledge) has been deduced directly or indirectly that way: what we can change "arbitrarily" must be the "cause" and what is "observed" is the consequence. Even the whole idea of a deterministic time evolution comes from those observations (and their theoretical extrapolations) in the first place.
Now, whether we "really" had some choice, or whether we were just passive observers of spurious correlations between disparate events (such as me suddenly having a desire to push the button which is the result of some brain activity) doesn't matter. What matters is that we know when things are "arbitrary choices" we (think we can) set, and which find their origin if not in free will, then in some processes that have "nothing to do" with the phenomenon that is to be observed.

Now, if we are going to claim, that the light went on just by some thermodynamical coincidence (suddenly, the random motion of the atoms in the wire increased a lot as a statistical fluctuation), and that, exactly at that time, in my brain, there was a process that gave me some desire to push the button, and that this coincidence repeats itself several times, then indeed, I will be fooled into thinking that there is a causal relation between me pushing the button, and the light going on, but in fact there is none. But then, ALL WE KNOW is based upon erroneous deductions of causal relationships which were in fact nothing else but funny coincidences.

This is different with your GR "experiment". In GR, if we don't use electromagnetism, we wouldn't "have the impression that we had the freedom to choose when the galaxies aligned". We would just be passively observe the galaxies evolve, see them align, and then see that our asteroids got pulled apart. We wouldn't have that same impression of 'being able to decide when we push the switch". Indeed, in a passively evolving system, where we cannot "arbitrarily decide", we don't know whether correlations represent cause-effect relationships. At no point, we would be fooled into thinking that we had a choice.

And finally, my argument against "unknown physics/conspiracies/..." to explain EPR correlations is this: quantum mechanics predicts them correctly. That means that all the physical knowledge of the mechanism is already included in one way or another in quantum theory. Now, we might not understand this totally, or quantum theory might be an "effective formalism" of a deeper theory of course. But it would be very strange that a superdeterministic theory of which we don't even have a clue how it might be put together (in such a way that samples of a song of Vera Lynn are correlated with the photon pairs emitted in a lab 60 years later) produces as only effect, exactly those effects that are nicely described by the current quantum formalism. A quantum formalism that was deduced by looking at observations that were often made by using "free choices" of settings to derive "causal relationships".

Again, I don't say that superdeterminism is impossible. But it stretches imagination (much more so, imo, than the extravagance of MWI!).

I have outlined several arguments:

1) The argument that was used against MWI in the beginning of this thread (namely, that MWI supposes a difference between observation and "reality", while that MWI was derived by looking at QM, which was a formalism that was derived by looking at observations, probably by people who thought that observations corresponded to reality), can be, in a much stronger form, used against superdeterminism:
If superdeterminism is true, then all "causal relationships" we've ever derived were the result of funny correlations without the slightest bit of causality. This includes all we think we know, because all our knowledge is based upon the assumption that free choices are uncorrelated with what is going to be observed.

2) There is not the slightest hint of an existing theory that does this, even though it is not impossible.

3) All that trouble for finding, finally, something that we know already: the EPR correlations are correctly predicted by quantum mechanics as we know it today.

He might believe that it goes round and round because of his "free will" but he can do nothing but "choose" to follow that trajectory.

He wouldn't. If he had the impression of free will, he would find correlations with several distinct phenomena. He could say: now, the planet will have the position given by a 'random number generator'. Next, he could say: now the planet will have the position given by samples of my favorite song. Next, he could say...
Of course, this is maybe not truly free will, but the point is that the correlations could be with just anything. If this happens, THEN he will have the impression of "being able to decide where the planet is". And if, as a function of that position of the planet, he observes certain phenomena (like tides on another planet or something), he might start to think that there is a causal relationship. But he wouldn't have that impression from just the planet following passively an orbit on which he "cannot decide" how to "change" it.

I'm not fooled into thinking that the sun's position is causally determined by the hands on my watch. If however, I can "change" the hands of my watch "arbitrarily" and the sun would "follow" instantaneously, then I would be quite puzzled. But for that, I have to be able to get the impression that I can freely change the position of the hands of my watch.

 

[tehno]

I first enountered Bohm's work some 50 years ago. It's still outside the mainstream, beause it has contributed little or nothing to further any branch of physics that's connected to experiments. My sense is that the arguments about Bohm have not changed much over the last 50 years.

To me,Bohm's work is an interesting approach how to interpret some aspects of QM.I don't see how it can contribute to any branch of experimental physics or predict something new what can't be predicted by an ortodox school of QM.Therefore ,as such,it's just a try to "see" what is in background of QM and its' equations. What would Einstein say about Bohm's interpretations?

 

[vanesch]

To me,Bohm's work is an interesting approach how to interpret some aspects of QM.I don't see how it can contribute to any branch of experimental physics or predict something new what can't be predicted by an ortodox school of QM.Therefore ,as such,it's just a try to "see" what is in background of QM and its' equations.

Right. That's also how I look upon Bohm (and MWI, btw).

What would Einstein say about Bohm's interpretations?

Now, that's an interesting question

He would have liked the "realist" aspect, and disliked the fact that relativity goes out of the window, I guess (but then, who am I to say what Einstein would have thought :shy: ...)

 

[Anonym]

Quote:

What would Einstein say about Bohm's interpretations?

Now, that's an interesting question.

He would have liked the "realist" aspect, and disliked the fact that relativity goes out of the window, I guess (but then, who am I to say what Einstein would have thought)

For your pleasure

A. Einstein to M.Born (12.5.1952):

”Did you see as Bohm (as by the way de Broglie 25 years ago) believes that the quantum theory may be interpreted deterministically otherwise? It, in my view, cheap consideration, however, your judgment is better indeed.”

Regards, Dany.

 

[ttn]

Now, that's an interesting question

He would have liked the "realist" aspect, and disliked the fact that relativity goes out of the window, I guess (but then, who am I to say what Einstein would have thought :shy: ...)

Actually, Einstein lived long enough to know about Bohm's theory. He famously remarked that it was "too cheap" and basically dismissed it. Vanesch is probably right that the main reason for this is that relativity goes out the window. It's also relevant that Einstein had more or less invented Bohm's theory himself about 40 years earlier, and had rejected it way back then precisely because it seemed to conflict with relativity. Einstein never got fully behind de Broglie's discovery of the same theory either, no doubt for about the same reason. And then, between the 20s (when de Broglie proposed this theory) and the 50s (when Bohm rediscovered it), Einstein had been working on his "unified field theory" idea, which was supposed to be some kind of massive replacement for QM which unified E&M and General Relativity and sort of "got underneath" the need for anything like the by-then-standard QM formalism. So I think that is basically what Einstein meant when he said Bohm's theory was "too cheap" -- it kept too much of the standard QM formalism, and just added something on top of it, something which *did not fix* what was for Einstein *the fundamental* problem with orthodox QM, namely the conflict with relativity. So while Einstein probably appreciated the conceptual clarity of Bohm's theory (relative to copenhagen) he didn't see Bohm as something that solved the fundamental problem, and simultaneously saw it as something that wasn't nearly radical enough in its break with orthodoxy. Hence, "too cheap".

However, unfortunately, Einstein did not live long enough to witness the next major development in this story, namely Bell's discovery (motivated by Bohm's theory, by the way... so much for the idea that Bohm's theory never led to any important new discoveries) that the non-locality (the anti-relativistic character) of Bohm's theory was *unavoidable* in any theory making (what we now know are) the empirically correct predictions for a certain class of experiments. So it wasn't, as Einstein thought, a matter of working to find a theory that would solve the fundamental problem with orthodox QM (its nonlocality), but rather of coming to grips with the fact that something is wrong or incomplete about relativity (or we've misunderstood it if we think it outlaws nonlocality). And once this is fully grasped (most still don't grasp it today), it removes completely the one otherwise-valid objection to Bohm's theory, namely that relativity goes out the window. If Einstein had lived long enough to see Bell's Theorem, he probably would have understood this and would have had a very very different reaction to Bohm's theory.

Sadly, though, that has to remain speculation.

 

[tehno]

However, unfortunately, Einstein did not live long enough to witness the next major development in this story, namely Bell's discovery (motivated by Bohm's theory, by the way... so much for the idea that Bohm's theory never led to any important new discoveries) that the non-locality (the anti-relativistic character) of Bohm's theory was *unavoidable* in any theory making

But wasn't Bell's discovery, you are reffering to,and associated experiments motivated also by Einstein's so called *spooky action at distance* thought experiment?
Famous "Quantum entanglement" ,and that our Universe is quantumly coupled (with or without relativity) are consequence of ortodox QM theory.
Or am I mistaken?

 

[Anonym]

Actually, Einstein lived long enough to know about Bohm's theory... If Einstein had lived long enough to see Bell's Theorem, he probably would have understood this and would have had a very very different reaction to Bohm's theory.

I read your essay- post #101. I have two questions:

1. Do you have professional education in physics?
2. If yes, who was your teacher?

In addition, I am not familiar with “what was for Einstein *the fundamental* problem with orthodox QM, namely the conflict with relativity”. A. Einstein never talks about nonexistent problems; the problem was formulation of consistent theory of measurements.

Regards, Dany.

 

[ueit]

Yes, but look at the following. We have the impression that we can "decide" about the settings of the polarizers. This means that we can essentially correlate this with almost any other phenomenon.

OK, but keep in mind that this "impression that we can "decide" doesn't mean much, especially when dealing with unintuitive experiments like EPR. We have also the impression that we don't exist in a superposition of states, that we live in a local universe, and so on. However, QM forces us to accept that at least some of these impressions are false, so why not drop the "free will" one?

And because all matter have the same basic components (mainly electrons and quarks) any "phenomenon" you choose as the source of "random" settings brings nothing new to the experiment. It is like trying to "fool" energy conservation by using all kinds of devices (chemical, mechanical, nuclear and so on) and wondering each time about the failure to do so. The explanation is the same. Energy conservation is enforced at the fundamental particle level and no matter how you play with different devices you cannot brake the law.

Now, I don't want to drift in a discussion here about "free will" - I can accept that free will is an illusion in a deterministic universe, but nevertheless, it has a meaning. The meaning is that the choices can be based upon "arbitrary" correlations (human brain states, photons coming from the back end of the universe, samples of songs sung long ago...).

In fact free will is not the problem here, and neither randomness (understood as a lack of pattern, not as a lack of cause), but only predictability. And I think we agree that in a deterministic world everything is predictable.

We have learned somehow, throughout the entire evolution of science (and even before that), that when things seem to depend upon "free will" that they are statistically independent. In fact, the whole endeveour of science is based upon that idea! "Controlled experiments" are nothing else but exactly that: we change "arbitrarily" some parameters while keeping others constant, and we deduce "causal relations" from that. You push arbitrarily the button, and you see the light go on. You do that 50 times, and you conclude that there is some causal relationship between you pushing the button as cause, and the light going on as consequence... maybe due to the current that will flow in the wire, or maybe for another reason. In fact, THE WHOLE OF SCIENCE (and all of our common sense knowledge) has been deduced directly or indirectly that way: what we can change "arbitrarily" must be the "cause" and what is "observed" is the consequence. Even the whole idea of a deterministic time evolution comes from those observations (and their theoretical extrapolations) in the first place.
Now, whether we "really" had some choice, or whether we were just passive observers of spurious correlations between disparate events (such as me suddenly having a desire to push the button which is the result of some brain activity) doesn't matter. What matters is that we know when things are "arbitrary choices" we (think we can) set, and which find their origin if not in free will, then in some processes that have "nothing to do" with the phenomenon that is to be observed.

1. I think you overestimate the importance of free choice here. There are branches of science where we are forced in the position of passive observers, like galaxy formation or paleontology.

2. Even in your example I don't see any problem. The causality remains, we still observe that whenever the button is pressed the light is on.

3. The device that sets the detector in an EPR experiment generates an EM field by its own existence. I don't see any good reason to assume that this field has "nothing to do" with the experiment.

Now, if we are going to claim, that the light went on just by some thermodynamical coincidence (suddenly, the random motion of the atoms in the wire increased a lot as a statistical fluctuation), and that, exactly at that time, in my brain, there was a process that gave me some desire to push the button, and that this coincidence repeats itself several times, then indeed, I will be fooled into thinking that there is a causal relation between me pushing the button, and the light going on, but in fact there is none. But then, ALL WE KNOW is based upon erroneous deductions of causal relationships which were in fact nothing else but funny coincidences.

You seem to be building a case against the "bag of events" hypothesis where we have coincidences without a causal, deterministic mechanism (the random fluctuation in the wire). I reject such conspiracy theories, just like you and I see no similarity between them and (super)determinism. On the contrary, I propose a causal connection between the generation of entangled particles and the surrounding fields. Nothing happens at random and there are no "erroneous deductions". The correlations are not an illusion, they reflect the underlying deterministic mechanism.

This is different with your GR "experiment". In GR, if we don't use electromagnetism, we wouldn't "have the impression that we had the freedom to choose when the galaxies aligned". We would just be passively observe the galaxies evolve, see them align, and then see that our asteroids got pulled apart. We wouldn't have that same impression of 'being able to decide when we push the switch". Indeed, in a passively evolving system, where we cannot "arbitrarily decide", we don't know whether correlations represent cause-effect relationships. At no point, we would be fooled into thinking that we had a choice.

The GR was meant to be an analogy for how QM interactions take place. So, you have to "replace" GR for EM-interactions wherever these appear, including the experimenter's brain. So, if QM is deterministic we are "passively evolving systems" just like the other parts of the experiment. So, the experimenter is a galaxy, the detector another one, a computer, if present, another one and so on. Regardless of what each "galaxy" does or believes, the asteroids (our entangled particles) "know" exactly the detector configuration at the detection time.

And finally, my argument against "unknown physics/conspiracies/..." to explain EPR correlations is this: quantum mechanics predicts them correctly. That means that all the physical knowledge of the mechanism is already included in one way or another in quantum theory.

Just like all chemistry "is already included in one way or another" in thermodynamics.

Now, we might not understand this totally, or quantum theory might be an "effective formalism" of a deeper theory of course. But it would be very strange that a superdeterministic theory of which we don't even have a clue how it might be put together (in such a way that samples of a song of Vera Lynn are correlated with the photon pairs emitted in a lab 60 years later) produces as only effect, exactly those effects that are nicely described by the current quantum formalism. A quantum formalism that was deduced by looking at observations that were often made by using "free choices" of settings to derive "causal relationships".

I find the alternatives no less strange and the possibility (even if remote) to recover the nice classical ontology in QM world very attractive. Again, you make it sound more unlikely that it is. After all a computer and a physicist will generate the same amount of energy per each Kg, they fall at the same speed, etc. Why not behave similarly in an EPR experiment too?
I agree that here it's not the place to discuss "free choice" but I think there are experiments proving that someone can be determined to "freely choose" what to do. I'll try to find some links and post them here and close this argument.

Again, I don't say that superdeterminism is impossible. But it stretches imagination (much more so, imo, than the extravagance of MWI!).

I have outlined several arguments:

1) The argument that was used against MWI in the beginning of this thread (namely, that MWI supposes a difference between observation and "reality", while that MWI was derived by looking at QM, which was a formalism that was derived by looking at observations, probably by people who thought that observations corresponded to reality), can be, in a much stronger form, used against superdeterminism:
If superdeterminism is true, then all "causal relationships" we've ever derived were the result of funny correlations without the slightest bit of causality. This includes all we think we know, because all our knowledge is based upon the assumption that free choices are uncorrelated with what is going to be observed.

No, superdeterminism is just the logically consistent determinism, and is completely different from "bag of events" conspiracy theories. Our "free choices" are certainly correlated with observation.

2) There is not the slightest hint of an existing theory that does this, even though it is not impossible.

Yeah, that's bad.

3) All that trouble for finding, finally, something that we know already: the EPR correlations are correctly predicted by quantum mechanics as we know it today.

I don't think it's useless to find a mechanism by which the statistical predictions of QM are accomplished.

He wouldn't. If he had the impression of free will, he would find correlations with several distinct phenomena. He could say: now, the planet will have the position given by a 'random number generator'. Next, he could say: now the planet will have the position given by samples of my favorite song. Next, he could say...
Of course, this is maybe not truly free will, but the point is that the correlations could be with just anything. If this happens, THEN he will have the impression of "being able to decide where the planet is". And if, as a function of that position of the planet, he observes certain phenomena (like tides on another planet or something), he might start to think that there is a causal relationship. But he wouldn't have that impression from just the planet following passively an orbit on which he "cannot decide" how to "change" it.

I'm not fooled into thinking that the sun's position is causally determined by the hands on my watch. If however, I can "change" the hands of my watch "arbitrarily" and the sun would "follow" instantaneously, then I would be quite puzzled. But for that, I have to be able to get the impression that I can freely change the position of the hands of my watch.

See above my clarification regarding the correct understanding of my analogy

 

[ttn]

But wasn't Bell's discovery, you are reffering to,and associated experiments motivated also by Einstein's so called *spooky action at distance* thought experiment?

You mean the EPR argument? That was an argument that a local explanation of certain correlations predicted by QM would require deterministic local hidden variables. (And secondarily that, as long as one accepts locality, orthodox QM is therefore incomplete since it doesn't contain those variables.) Or put it this way: EPR proved that *the only hope for locality* is a certain specific type of hidden variable model.

Bell's theorem is then that this can't work, that the one kind of model that EPR showed *might* be able to explain things locally, can't. So *nothing* can explain things locally. Non-locality is a real fact of nature.

Famous "Quantum entanglement" ,and that our Universe is quantumly coupled (with or without relativity) are consequence of ortodox QM theory.
Or am I mistaken?

I don't really understand what you said. Orthodox QM is not a local theory. That's the whole point of EPR. What bothered Einstein was the spooky action at a distance that OQM posited. He hoped to get rid of that by introducing something like the hidden variables I mentioned above. But Bell proved that that won't work -- you can't get rid of the non-locality (and keep the right empirical predictions, *even* by adding hidden variables). So non-locality is a real fact of nature.

 

[ttn]

I read your essay- post #101. I have two questions:

1. Do you have professional education in physics?
2. If yes, who was your teacher?

I don't quite see why you are asking this, but...

1. Yes. I have a BS in physics (w/ a philosophy double major) from a top science college, and a PhD in physics from a top-20 university, and I'm a tenured professor of physics at a small college.

2. I've had lots of teachers.

In addition, I am not familiar with “what was for Einstein *the fundamental* problem with orthodox QM, namely the conflict with relativity”. A. Einstein never talks about nonexistent problems; the problem was formulation of consistent theory of measurements.

Einstein makes clear in a few places that for him it is the non-localilty of orthodox QM which is his major issue with it. See, e.g., some of the passages quoted in this paper:

http://www.physics.princeton.edu/~mcdonald/examples/QM/norsen_ajp_73_164_05.pdf

 

[vanesch]

OK, but keep in mind that this "impression that we can "decide" doesn't mean much, especially when dealing with unintuitive experiments like EPR. We have also the impression that we don't exist in a superposition of states, that we live in a local universe, and so on. However, QM forces us to accept that at least some of these impressions are false, so why not drop the "free will" one?

First a note:
I hope you understood that by free will, I understand also "correlations with seemingly unconnected phenomena" which is necessary if we are going to consider superdeterministic systems.

I tried to point out that what we call "free will" is maybe an erroneous impression of "freedom", but has nevertheless a rather precise meaning, in that we seem to be able to set up experiments of which the "freely decided parameters" are "determined" by just any arbitrary phenomenon (samples of songs, photons from the back end of the universe, noise in a warm resistor...). Now, in a superdeterministic setting, of course all these things are determined by the initial conditions, and so, are not really 'freely chosen'.

However, as I tried to point out, about all we know, and even the very suggestion of determinism, has been "found out" by making the assumption that "freely chosen parameters" (in the above sense) are statistically independent of the phenomenon we are trying to study. It is a fundamental hypothesis in all we learned about cause-effect relations, from our childhood experiences (the hot stove burns the finger, it is not the burning finger which heats the stove) to all scientific experiments. If we let this go, then everything we've ever learned was just a big conspiracy, and there is no difference between a superdeterministic universe, and a "bag of events" universe, because we will never be able to find out the real cause-effect relations if we cannot make the above hypothesis of statistical independence of "freely chosen parameters".
Moreover, there would be no reason why things APPEAR to us, most of the time, to have this statistical independence! There is no reason, if we have to accept EPR correlations as being superdeterministic effects (and hence, that there are statistically non-trivial links between the samples of old songs, the photons coming in from the back end of the galaxy, and the movement of charges in a warm resistor), that there shouldn't be OTHER strange correlations all around us. It would be totally incomprehensible that, no matter all these strange correlations that have to pop up whenever they are used in an EPR experiment (and they can be related to ANYTHING a priori), they DON'T pop up when we do the direct correlation (that is, when not using them in an EPR experiment). Once we reach such a level of conspiracy in nature, there is no hope to discover anything !

And because all matter have the same basic components (mainly electrons and quarks) any "phenomenon" you choose as the source of "random" settings brings nothing new to the experiment. It is like trying to "fool" energy conservation by using all kinds of devices (chemical, mechanical, nuclear and so on) and wondering each time about the failure to do so. The explanation is the same. Energy conservation is enforced at the fundamental particle level and no matter how you play with different devices you cannot brake the law.

Yes, but then the question is: why do these strange and long-range correlations between all kinds of events don't show up when we don't use them to do the polarizer settings (I'm not aware of any specific correlations observed between samples of songs, photons from the CMB, noise in resistors and so on whenever these are NOT used as settings in an EPR experiment), and suddenly pop up when they need to, just in order to make the right correlations come out with a pair of photons with which they didn't have anything special to do a priori.

In other words, why would we have this impression of statistical independence of "freely settable parameters" (from which we deduced about all we know about causal relationships in the first place!) if this is in general not true, but would this ONLY show up in some very peculiar settings ? This is simply too much conspiracy to me ; worse, this working hypothesis would undermine everything we knew up to now !

1. I think you overestimate the importance of free choice here. There are branches of science where we are forced in the position of passive observers, like galaxy formation or paleontology.

Yes, but these branches rely on other branches, where causal relationships HAVE been established, and where we make hypotheses of statistical independence of causes with their effects. If the act of digging would make atoms migrate (by "coordinated thermal fluctuations") into configurations of dinosaur bones (hey, creationists never thought of THIS argument ) the whole basis of paleontology would be erroneous.

2. Even in your example I don't see any problem. The causality remains, we still observe that whenever the button is pressed the light is on.

No, we could say that the fact that light goes on makes the button be pressed in this case.

3. The device that sets the detector in an EPR experiment generates an EM field by its own existence. I don't see any good reason to assume that this field has "nothing to do" with the experiment.

That "device" can be a galaxy 2 million light years away, or the decay of a radioactive atom, or the noise in a resistor, or a combination of all that. It is difficult to see how all these things can have a very precise causal link to the emitted pair, while we've never observed individually such a causal link. This is worse than astrology!

 

[Anonym]

I don't quite see why you are asking this

I have impression that the old traditions of the scientific discussion that were established during the centuries somehow lost during last 50 years and are substituted by the American dreams of self-promotion. I am not sure that you comprehend what you wrote above (see quotation).

I consider legitimate when one present his view or his interpretation of POV of somebody else. I do not consider it fair to use A. Einstein name in order to assert just the opposite. If you have different opinion, defend it by your own. In addition, I am not familiar with the experimental results that support your statements. Your description of A. Einstein idea of unification of EM and GR also has nothing to do with the origin. A. Einstein looked for the solution within classical physics and without reference to QM (indeed QT should allow unification of all four fundamental interactions). Maybe attempt to understand his statements literally is also legitimate?

AB paper and the unambiguous confirmation provided by A. Tonomura et al demonstrated that “hidden” variables are present in CED and became transparent in QED. Thus, it seems that D. Bohm looked in the opposite direction. I do not think that A. Einstein understanding of physics depend on J.S. Bell “discovery”. I even don’t know what you mean. If you mean Bell’s inequalities I don’t understand what news about QM they tell us in addition to thousands experiments that demonstrate that non-relativistic limit of QT is adequate and complete. I will understand your statements about nonlocality if you will demonstrate it theoretically in the absence of the time dispersion or experimentally.

Regards, Dany.

 

[tehno]

I don't really understand what you said. Orthodox QM is not a local theory. That's the whole point of EPR. What bothered Einstein was the spooky action at a distance that OQM posited. He hoped to get rid of that by introducing something like the hidden variables I mentioned above. But Bell proved that that won't work -- you can't get rid of the non-locality (and keep the right empirical predictions, *even* by adding hidden variables). So non-locality is a real fact of nature.

Yes. I meant EPR and that QM isn't local theory.
Funny thing to me is that in early days it was created to describe local phenomena that couldn't be described by a classical physics (example: atom ).It overgrew it's inital purpose-->principles and formed equations signalized it could be more than just local.Possibility that the eqs. could describe QM systems with separated particles worried Einstein becouse of the finite speed of interaction propagation ( light velocity).
By the *biggest* hidden variable ,as matter of fact.I consider variable of time.But that's not really hidden variable ,just the one we don't understand enough.I would be interested to hear in what relationship stand Wheeler-Feynman transcription theory that led to QED and Bohmian interpretation of QM?
Bohm introduced so called pilot waves.Right ?

 

[Anonym]

By the *biggest* hidden variable ,as matter of fact, I consider variable of time. But that's not really hidden variable, just the one we don't understand enough.(at all, D.)

That is all point made by the “fathers”.

E. Schrödinger: "Matter stand much the same with another system, the electromagnetic field. Its laws are "relativity personified", a non-relativistic treatment being in general impossible".

Time is the special relativity all about. A. Einstein (5th Solvay) demonstrated that the collapse not only consistent but necessary to maintain relativity. And QT is obviously not complete since the relativistic version still not formulated. With all my respect to cats in general and to the Schrödinger cat in particular, I suggest to read carefully all E. Schrödinger paper, "Die gegenwärtige Situation in der Quantenmechanik", Naturwissenschaften 23: pp.807-812; 823-828; 844-849 (1935), English translation in W@Z. He never mentioned non-locality (the idea so remote from his attitude to the matter that …). In addition, in “The role of wave function in QED” here in PF you may find discussion presented by Hans de Vries (post #43, especially -8- and post #44) which I consider enlighten.

Regards, Dany.

 

[tehno]

Thank you for the references.
Our experience and senses ("What we see..") are still great
obstacles for interpretation of QM. Consider the following:
Classical (non-relativistic) mechanics rely on Newton's law of motion :F=ma.
This equation is an axiom (independent,can't be derived).
Understanding that equation ,for most of the humans,isn't problem.
Interpreting it's consequences isn't too hard also.
The reason is ,most likely,our senses are evolutionary adjusted to everydays
Newtonian world.
Similarily there's is a Shrodinger's equation in QM.
But what our senses can say about it (let alone logical interpretations of its' consequences)?
[Erratum:Of course ,in my previous post I meant W-F transactional -and not "transcription" theory ]

 

[rewebster]

Without a good definition of "TIME", anything is theoretically possible in some theories--EVEN time travel

How many 'time' worlds exist in MWI (or its sub-theories/interpretations/etc.)?

 

[Anonym]

Classical (non-relativistic) mechanics rely on Newton's law of motion :F=ma.This equation is an axiom (independent,can't be derived).

No. Newton's law of motion as well as every law of motion in physics is derivable from the Principle of Least Action. Notice that it has purely wave mechanical nature.

Understanding that equation ,for most of the humans,isn't problem. Interpreting it's consequences isn't too hard also.
The reason is ,most likely,our senses are evolutionary adjusted to everydays
Newtonian world.

I am not sure that it was so 300 years ago. Our intellectual abilities are also evolutionary adjusted. I have no doubt that after 300 years kids will study QFT in high school and will not understand why we had any problems of understanding.

Our everyday classical world also contains the EM and gravitation fields. If you believe that our senses are evolutionary adjusted to everyday world than it is only matter of patience, acquisition of relevant knowledge and time to reach understanding. I do not believe that with quantum world the story will be different. When A.Tonomura presents his pictures, I see the single electron in the specific waveform after it changes due to interaction with the beam splitter. By the way, I consider it the extremely beautiful pictures. I see pictures from the bubble chambers. I consider it the extremely beautiful pictures too. I have no difficulties to understand them and I do not need M. Born for that. I do not feel the size of time (time dispersion) but A. Einstein said that " Raffinert ist der Herr Gott, aber boshaft ist Er nicht".

Regards, Dany.

 

[ueit]

First a note:
I hope you understood that by free will, I understand also "correlations with seemingly unconnected phenomena" which is necessary if we are going to consider superdeterministic systems.

I tried to point out that what we call "free will" is maybe an erroneous impression of "freedom", but has nevertheless a rather precise meaning, in that we seem to be able to set up experiments of which the "freely decided parameters" are "determined" by just any arbitrary phenomenon (samples of songs, photons from the back end of the universe, noise in a warm resistor...). Now, in a superdeterministic setting, of course all these things are determined by the initial conditions, and so, are not really 'freely chosen'.

I understand how you define free will, no problem. I want to add something else to your last statement, which I consider very important. Not only all events, including choices are determined by initial conditions but they are also constrained. In the solar system, for example, one cannot change the orbit of Mercury while keeping all others the same. This is different from the "bag of events" hypothesis where any configuration is possible.

However, as I tried to point out, about all we know, and even the very suggestion of determinism, has been "found out" by making the assumption that "freely chosen parameters" (in the above sense) are statistically independent of the phenomenon we are trying to study.

I disagree.

It is a fundamental hypothesis in all we learned about cause-effect relations, from our childhood experiences (the hot stove burns the finger, it is not the burning finger which heats the stove) to all scientific experiments.

The real cause in a superdeterministic system is the past state of the whole system. It's not the Sun which causes Earth's motion neither is Earth which causes Sun's motion. However, one may assume one of the above and the observations are still valid. The equations describing the solar system evolution do not stand or fall on how one chooses the cause. The only thing that matters is the law of motion and not which causes what. I'd like to remind you of one of your arguments. You said that even if one assumes a flat Earth when building a telescope it doesn't follow that an observation pointing to a round Earth should be rejected.
You press the button and the light is on. The real cause in this case is the past state of the whole system, you, the button, the bulb, etc. This doesn't mean that the observation that the light is on when the button is pressed is false, or that we cannot use the observation in making an electrical network in a building.
I think the problem is similar to that of choosing a frame of reference. In the Newtonian picture, I can postulate that Pluto is THE free agent in our solar system and all other objects just follow its "choices". Then I can calculate Earth's future positions for different such "choices" and guess what? I get the right answer.

Moreover, there would be no reason why things APPEAR to us, most of the time, to have this statistical independence!

Oh, but there is a very good reason. It is true that, according to my hypothesis, every particle "knows" about its detection and is emitted only when the surrounding fields indicate a "favorable" detector. However, for an ordinary assembly of particles the correlations are hidden because we don't know when each of them is emitted. The entangled particles are generated both at the same time, therefore we have a very special case.

Yes, but these branches rely on other branches, where causal relationships HAVE been established, and where we make hypotheses of statistical independence of causes with their effects. If the act of digging would make atoms migrate (by "coordinated thermal fluctuations") into configurations of dinosaur bones (hey, creationists never thought of THIS argument ) the whole basis of paleontology would be erroneous.

The resulting theory would necessary make identical predictions with Darwin's theory It's only a very unnatural reference frame. And everybody knows that the devil put those bones there, to fool us.

No, we could say that the fact that light goes on makes the button be pressed in this case.

Same as above.

I have a question for you about the transactional interpretation. It seems to me that TI is pretty close to my hypothesis, if the advanced wave is not going into the past but in the "normal" way. The delayed choice experiments are dealt with by the superdeterministic character of the universe.

 

[tehno]

No. Newton's law of motion as well as every law of motion in physics is derivable from the Principle of Least Action.

What do you think why Newton's second Law is called a law and axiom in classical mechanics?Why is Principle of Least action called the "principle" -not law or even less axiom, what makes the difference ?? .The main reason isn't just level of complexity .You can find it actually behind one word in the following text:

Newton's second law F = ma states that the instantaneous force F applied to a mass m produces an acceleration a at the same instant. By contrast, the action principle is not localized to a point; rather, it involves integrals over an interval of time and for fields extended region of space. classical action principles, the initial and final states of the system.Say :Given that the particle begins at position x1 at time t1 and ends at position x2 at time t2, the physical trajectory that connects these two endpoints is an extremum of the action integral.
In particular, the fixing of the final state appears to give the action principle a teleological character which has been controversial historically. This apparent teleology is eliminated in the quantum mechanical version of the action principle.

 

[reilly]

Consider an elastic scattering measurement, say electron-proton scattering. Then, once I have measured, say, the electron's momentum, I know immediately what the momentum of the proton will be. In fact, The relationship of entanglement between electron and proton, can be further confirmed by coincidence detection experiments. We can have strong confidence that, neglecting radiation for the moment, if the proton could travel through a pipe after collision, we could do variants of momentum and spin measurements -- as in polarization measurements, and, of course, after similar measurements are made on the electron.

We do this sort of reasoning all the time; we trust our basic conservation laws.But, it seems to me, that we assume such things as rotational invariance is instantaneous, that is that angular momentum is conserved -- which it seems to be.. On the other hand, the universe we perceive is not "instantaneous", but is a historical record -- we only know now locally.

It seems to me that we are dealing with a broader issue than QM; that is, why do we assume that rotational invariance is true? Many experiments show this invariance has a very strong empirical basis. And we have elegant arguments and methods which we use in many branches of physics. But, how far do we know from? Suppose that we could manipulate something the size of the moon, and get it spinning like crazy. How long does it take for an observer a light year away to know about the spinning object? (By means, of course, of very sensative measurements.) The instantaneous version of angular momentum conservation would say: the distant observer should know immediately. That does not seem to happen.

I guess the question is:why exactly can we believe that QM, and CM in my view, gives the 'right" answers to entanglement problems, as they seem to do? My growing sense is that there's something about space we are not getting -- one could argue that info from conservation laws flows to all parts of the universe instantaneously. But, that is not a very satisfying argument.

One can also argue that our assumed structure of space -- isotropic, homogeneous, and so forth -- requires instantaneous propegation of conservation info.

It's crazy making.
Regards,
Reilly Atkinson