Why is superdeterminism not the universally accepted explanation of nonlocality?

[jadrian]

OK, let me give you an example of why you need special initial conditions.

In a deterministic theory, in order to predict the current behavior of any object, you need to know the initial conditions of the object, as well as the deterministic laws of the universe. In Newtonian mechanics, for example, you need to know the positions and velocities of all the particles at time t=0, and then F=ma will tell you the behavior of the particles at all later times.

Now let's consider what a local deterministic explanation of entanglement would look like. Let particles A and B be an entangled pair of photons, which are separated by a great distance and then sent through polarization detectors. We also have particles C and D: C tells the experimenter what angle he should set the polarizer that measures A, and D tells the experimenter how to set the polarizer that measures B. You can think of C and D as neurons in the brains of the experimenters if you like.

Now we find experimentally that the behavior of particle A through its measurement device is strongly correlated with the angle at which B's measurement device is set. And that angle is determined by particle D. So we have a correlation between the behavior of particles A and D.

But particles A and D are separated by such a large distance, so they cannot communicate with each other to coordinate their behavior (unless you have a nonlocal theory like Bohmian mechanics which allow undetectable faster-than-light signalling between particles). So a local determinist has to conclude that A and D are correlated not based on a current relationship between the present states of A and D, which would be impossible, but based on a past relationship of the initial states of A and D.

This is what we mean by special initial conditions: A and D seemingly have nothing to do with each other. After all, it is A and B that were in the entangled state, and yet somehow we have to conclude that the initial conditions of A and D had to be specially set so that a correlation between A and D would be observed in the future. And instead of just D, we can have a large number of particles D1, D2, D3,... which together determine the measurement setting, so the initial state of particle A had to have been set based on the initial states of all these particles. And in the real world, almost all particles in the universe are interacting in some way with almost all other particles, so really the setting of measurement device depends on almost everything in the universe, from which we conclude that the initial conditions of the whole universe were specially set so that the right kind of correlation would be displayed billions of years later between particle A and the measuring device.

This is why superdeterminism is called "conspiratorial". That doesn't mean it's wrong, it just has some issues which make it rather difficult to construct a viable superdeterministic theory, but let me repeat that some potential first steps toward such a theory have already been taken by a few people.

yeah but how can you POSSIBLY rule out that a and d did not interact in the past.

 

[jadrian]

it seems that the willingness of many people in this thread to discount superdeterminism offhand speaks more to an attempt to cling on to neo-vitalistic notions of free will than actual interest in science.

exactly

also again who has proof that a and d could not have interacted in the past

 

[jadrian]

After all, it is A and B that were in the entangled state, and yet somehow we have to conclude that the initial conditions of A and D had to be specially set so that a correlation between A and D would be observed in the future.

SPECIALLY SET? CAUSALITY SPECIALLY SETS EVERYTHING OTHERWISE THERE WOULDNT BE CAUSALITY!

 

[jadrian]

Yeah, that's all I had seen as well.

As you say, after a while you realize that every single particle in the universe would need to carry a local copy of all the information regarding every other particle as well. Plus a lot more information, I think, to handle the large number of possible Bell tests that could be performed.

The entire direction then takes on the attributes of an ad hoc theory, which immediately means no novel predictions will likely be forthcoming (that's what happens when you go into ad hoc mode). So I would say the outlook is bleek in terms of future prospects, and further that most scientists share this view in one way or another.

I think you view superdeterminism as a way AROUND bells tests. I think superdeterminsm makes bells tests look like an absolute waste of time.

 

[jadrian]

Yeah, that's all I had seen as well.

As you say, after a while you realize that every single particle in the universe would need to carry a local copy of all the information regarding every other particle as well. .

.

local copy? information isn't copied! i can't punch a wall without breaking my knuckles! me punching the wall might put a dent in it and that dent represents some info i transferred to the wall. the wall didnt store the full information of the event! the wall had just as much info transfer to my hand! what makes you think all the information about this event would get stored in the wall and my knuckles as if we made a xerox of every bit of information in every particle in the wall and every particle in my hand and this info gets stored forever in the wall and in my hand? how do causal interactions give you the philosophy that every particle is storing all other particles information? its only storing a finite amount of information it obtained from events which happened to it in the past!

the universe as a whole contains all this information AND IF YOU HYPOTHETICALLY HAD ALL THE INFORMATION IN THE UNIVERSE YOU WOULD KNOW EXACTLY WHAT WILL HAPPEN IN THE FUTURE WITH DEFINED DETERMINISM AND ABSOLUTE CERTAINTY. AND SINCE ALL THE INFORMATION IN THE UNIVERSE EXISTS, THE FUTURE WILL HAPPEN WITH DEFINED DETERMINISM., even tho it is impossible to obtain all this information.

why is this such a hard pill to swallow, unless you believe in free will? if i could hypothetically rewind time like a videotape, and re perform an electrons position measurement, i would get the exact same result! otherwise we would have to regard the past as undetermined at a given location.

doesnt anybody find the free will assumption of the copenhagen interpretation to be hysterical?

 

[IttyBittyBit]

jadrian, speaking in all caps does not assist in getting your point across. I'm trying to defend your viewpoint, don't make me look like an idiot for doing so.

 

[jadrian]

First, since that nonlocality and entanglement are perfectly compatible with a non-deterministic viewpoint, the problem does not even exists.

Second, from a theoretical point of view determinism arises when one consider a certain kind of simple systems as the traditionally studied in physics.

Third, the assumption that universe is deterministic is outside the scope of science.

assumption? it should be trivial! the past is defined but the future you suppose isnt?

take this example. the word "could've", HAS NO MEANING, and should be abolished from the english language. maybe if they did that, the next generation of scientists would be all over superdeterminism, as opposed to free will, santa, the tooth fairy etc...

 

[jadrian]

jadrian, speaking in all caps does not assist in getting your point across. I'm trying to defend your viewpoint, don't make me look like an idiot for doing so.

sorry i just don't understand how these concepts are not blatantly obvious to people.

 

[jadrian]

Occam's razor makes it hard to justify invoking a conspiratorial explanation like superdeterminism.
No, a lot of work is not being done on superdeterminism.

occams razor should lead you to a deterministic viewpoint. its so simple.
even in your experiment with entanglement a and b and particles c and d, can you prove that information had not been transmitted between a and d in the history of the universe?

 

[jadrian]

And in the real world, almost all particles in the universe are interacting in some way with almost all other particles, so really the setting of measurement device depends on almost everything in the universe, from which we conclude that the initial conditions of the whole universe were specially set so that the right kind of correlation would be displayed billions of years later between particle A and the measuring device

speaking of conspiratorial, this experiment could never theoretically be carried out, seeing as your large distance statements imply that a and d are outside each others lightcones. and as we came from a singularity according to bbt, at what point since the big bang did causality cease to exist? because noncausality is the only way i can think of particles a and d having never interacted in some form.

 

[jadrian]

local copy? information isn't copied! i can't punch a wall without breaking my knuckles! me punching the wall might put a dent in it and that dent represents some info i transferred to the wall. the wall didnt store the full information of the event! the wall had just as much info transfer to my hand! what makes you think all the information about this event would get stored in the wall and my knuckles as if we made a xerox of every bit of information in every particle in the wall and every particle in my hand and this info gets stored forever in the wall and in my hand? how do causal interactions give you the philosophy that every particle is storing all other particles information? its only storing a finite amount of information it obtained from events which happened to it in the past!

the universe as a whole contains all this information AND IF YOU HYPOTHETICALLY HAD ALL THE INFORMATION IN THE UNIVERSE YOU WOULD KNOW EXACTLY WHAT WILL HAPPEN IN THE FUTURE WITH DEFINED DETERMINISM AND ABSOLUTE CERTAINTY. AND SINCE ALL THE INFORMATION IN THE UNIVERSE EXISTS, THE FUTURE WILL HAPPEN WITH DEFINED DETERMINISM., even tho it is impossible to obtain all this information.

why is this such a hard pill to swallow, unless you believe in free will? if i could hypothetically rewind time like a videotape, and re perform an electrons position measurement, i would get the exact same result! otherwise we would have to regard the past as undetermined at a given location.

doesnt anybody find the free will assumption of the copenhagen interpretation to be hysterical?

hey sorry to get so excited, its just nobody has addressed what i consider paradoxical,--- the possibility that causality did not govern the universe at some point in time. this notion is just full retard to me

 

[jadrian]

local copy? information isn't copied! i can't punch a wall without breaking my knuckles! me punching the wall might put a dent in it and that dent represents some info i transferred to the wall. the wall didnt store the full information of the event! the wall had just as much info transfer to my hand! what makes you think all the information about this event would get stored in the wall and my knuckles as if we made a xerox of every bit of information in every particle in the wall and every particle in my hand and this info gets stored forever in the wall and in my hand? how do causal interactions give you the philosophy that every particle is storing all other particles information? its only storing a finite amount of information it obtained from events which happened to it in the past!

the universe as a whole contains all this information AND IF YOU HYPOTHETICALLY HAD ALL THE INFORMATION IN THE UNIVERSE YOU WOULD KNOW EXACTLY WHAT WILL HAPPEN IN THE FUTURE WITH DEFINED DETERMINISM AND ABSOLUTE CERTAINTY. AND SINCE ALL THE INFORMATION IN THE UNIVERSE EXISTS, THE FUTURE WILL HAPPEN WITH DEFINED DETERMINISM., even tho it is impossible to obtain all this information.

why is this such a hard pill to swallow, unless you believe in free will? if i could hypothetically rewind time like a videotape, and re perform an electrons position measurement, i would get the exact same result! otherwise we would have to regard the past as undetermined at a given location.

doesnt anybody find the free will assumption of the copenhagen interpretation to be hysterical?

let me clarify my pov. in a universe governed by causality, there is nothing conspiratorial about a particle essentially knowing about every other particle in the universe. if i am a particle that bumped into another particle in the past, based on my change in state/momentum/whatever, i will have information about that other particle ie where it is headed, how fast its moving, the fact that it exists etc. that particle likewise now has info on me. we basically traded information. if the particle i bumped into hits another particle, it will be transffering info to the third particle, but that info transferred in the second particle collision has my information in it. so if i was particle a which first collided with b and then b collided with c, i would have INTERACTED with particle c without ever seeing it or coming near it.

im using a simple example to show how particles in the universe have all interacted, without the need for it to be regarded as a conspiracy.

through the many modes of information propagation, even the gravitational information produced by an electron, it seems totally reasonable that this is the reason for particles effectively knowing about each other, because if they could trace all of their event histories through the past, they would see how they have all essentially interacted and are now correlated, the word used in the a b c d thought experiment.

and if we all originated from a single point singularity, i don't know how causality would not be governing then, or at least asymptoticly close in time to when the singularity exploded.

so cause and effect in mind i simply don't understand how all particles having essentially dirt on each other needs to be regarded as a conspiracy, unless as I've stated before, there was a time when causality did not govern.

the fact that something exists/is obsevrable/can have effects on other things, to me proves causality, otherwise what could be considered to be able to create something, God?

 

[juanrga]

assumption? it should be trivial! the past is defined but the future you suppose isnt?

take this example. the word "could've", HAS NO MEANING, and should be abolished from the english language. maybe if they did that, the next generation of scientists would be all over superdeterminism, as opposed to free will, santa, the tooth fairy etc...

One of the most beautiful aspects of science is how has proved wrong to that 'clever' people who believed that reason was enough to understand how world works.

Maybe it is time for you to learn what is science, what is the scientific method, and why determinism is based in faith. I wrote two encyclopedic articles about such issues, but acceptable discussions are given in many books, encyclopedias, and other references.

 

[DrChinese]

why is this such a hard pill to swallow, unless you believe in free will? if i could hypothetically rewind time like a videotape, and re perform an electrons position measurement, i would get the exact same result! otherwise we would have to regard the past as undetermined at a given location.

Free will is not a necessary component of QM. So I certainly am not rejecting superdeterminism because of that. I reject superdeterminism as an explanation for Bell test results, and I do so for the reasons already stated.

Please bear in mind that there are no candidate superdeterministic theories to reject at this point, so it is a moot point in many ways. The reason I mention the amount of local information to be stored in every particle is because a candidate theory will end up postulating this (in some form or fashion) as a way to explain Bell test results. It is not necessary to assume free choice for measurement settings in any stage of the argument, but you must explain how (i.e. the exact mechanism, since we have no other reason to suspect it exists) the choice is propagated in a superdeterministic candidate.

Not so easy, I assure you. Which is again, the answer to your original question.

 

[DrChinese]

let me clarify my pov. in a universe governed by causality, there is nothing conspiratorial about a particle essentially knowing about every other particle in the universe. if i am a particle that bumped into another particle in the past, based on my change in state/momentum/whatever, i will have information about that other particle ie where it is headed, how fast its moving, the fact that it exists etc. that particle likewise now has info on me. we basically traded information. if the particle i bumped into hits another particle, it will be transffering info to the third particle, but that info transferred in the second particle collision has my information in it. so if i was particle a which first collided with b and then b collided with c, i would have INTERACTED with particle c without ever seeing it or coming near it.

That is just NOT true in any meaningful sense. A particle has only a few observable elements: momentum, position, mass, charge, spin, color, etc. It would be instructive to state specifically how you would know ANY information about the past interactions by knowing these. Suppose the spin is +1. What does that tell you? Or momentum is 1.63 (units ignored) in direction XYZ? Not much history to be gained from that!

No, you need there to be a rich hidden internal structure. One that contains the entire initial conditions of the universe, like DNA. And this DNA would need to be in every particle so they know how to react during Bell tests.

 

[lugita15]

yeah but how can you POSSIBLY rule out that a and d did not interact in the past.

I can't rule out the possibility that A and D interacted some time in the past, and I didn't claim I could. I was just explaining why special initial conditions have to be chosen in order for a local deterministic theory to pass a Bell test.

 

[lugita15]

SPECIALLY SET? CAUSALITY SPECIALLY SETS EVERYTHING OTHERWISE THERE WOULDNT BE CAUSALITY!

Any deterministic theory has causality. But if you have some arbitrary deterministic theory and some arbitrary initial conditions, chances are you won't get the nonlocal correlations necessary to match the results of Bell tests. It's only if you have very specific initial conditions, conditions where the initial state of each particle is set based on the initial states of all other particles, that you get the right kind of nonlocal correlations. That's what makes superdeterminism conspiratorial.

Let me repeat, that does not mean superdeterminism is ruled out, it just means there are hurdles that any superdeterministic theory has got to face.

 

[lugita15]

speaking of conspiratorial, this experiment could never theoretically be carried out, seeing as your large distance statements imply that a and d are outside each others lightcones. and as we came from a singularity according to bbt, at what point since the big bang did causality cease to exist? because noncausality is the only way i can think of particles a and d having never interacted in some form.

Again, I am not claiming that A and D could never have interacted. I am saying that the interaction of A and D would have to have occurred in just the right way so that they would demonstrate nonlocal correlations of just the right kind. And by similar arguments, you would have to conclude that at the beginning of the universe all the particles interacted with each other to set just the right initial states for each particle, so that all the Bell tests which would be performed in the entire history of the universe would get just the right results. That's what's called a conspiracy.

 

[jadrian]

One of the most beautiful aspects of science is how has proved wrong to that 'clever' people who believed that reason was enough to understand how world works.

Maybe it is time for you to learn what is science, what is the scientific method, and why determinism is based in faith. I wrote two encyclopedic articles about such issues, but acceptable discussions are given in many books, encyclopedias, and other references.

reason is capable of intuitively understanding our universe in my opinion, and einsteins. i don't draw pictures of what i think the world should look like, but I am also not like a lab rat who gets a false reading and takes a swing at einstein only to get their arm torn off.

 

[jadrian]

i get it, people psychologically can't function or live happily with the idea that everything they do is already predetermined. all ill say is most of my life i believed in free will, but all you have to do is think very deeply and ask yourself, how could you have possibly done anything different than the way you did it?

 

[lugita15]

let me clarify my pov. in a universe governed by causality, there is nothing conspiratorial about a particle essentially knowing about every other particle in the universe.

No, there isn't, but there is something conspiratorial about a particle behaving in just the right way based on the information it has about what other particles are going to do at just the right time and place.

if i am a particle that bumped into another particle in the past, based on my change in state/momentum/whatever, i will have information about that other particle ie where it is headed, how fast its moving, the fact that it exists etc. that particle likewise now has info on me. we basically traded information. if the particle i bumped into hits another particle, it will be transffering info to the third particle, but that info transferred in the second particle collision has my information in it. so if i was particle a which first collided with b and then b collided with c, i would have INTERACTED with particle c without ever seeing it or coming near it.*

im using a simple example to show how particles in the universe have all interacted, without the need for it to be regarded as a conspiracy.

Again, particles interacting and transferring information is not regarded as a conspiracy. It's a conspiracy if their interaction induced some very special behavior on their part which leads to a Bell-type nonlocal correlation.

 

[Joncon]

reason is capable of intuitively understanding our universe in my opinion, and einsteins. i don't draw pictures of what i think the world should look like, but I am also not like a lab rat who gets a false reading and takes a swing at einstein only to get their arm torn off.

Einsten told us that the speed of light would be measured the same regardless of how fast we were travelling. Is that intuitive? His theories also tell us that a spaceman who travels around the galaxy for a while and returns to Earth will be younger than his twin. That's certainly not intuitive either. Our intuition has evolved to help us in everyday life, and it works well, but on an atomic scale it's obviously lacking.

i get it, people psychologically can't function or live happily with the idea that everything they do is already predetermined. all ill say is most of my life i believed in free will, but all you have to do is think very deeply and ask yourself, how could you have possibly done anything different than the way you did it?

I'm not sure there are too many scientists who believe in free will (maybe I'm wrong), but you don't need superdeterminism to rule it out. As long as you accept that certain things in the universe happen randomly then the future isn't already mapped out. It doesn't mean you have any more "control" over your actions, just that you can't predict them.

 

[jadrian]

No, there isn't, but there is something conspiratorial about a particle behaving in just the right way/QUOTE]

you said a and d were correlated. saying "just the right way" implies more than correlation in my mind

 

[lugita15]

you said a and d were correlated. saying "just the right way" implies more than correlation in my mind

To repeat, in order to have Bell-type nonlocal correlations between A and D in a local deterministic theory, we need A and D not only to have interacted in the past, but to have interacted in just the right way so that they would get the right "conspiratorial" initial conditions so that they would display the right kind of nonlocal correlations years later.

 

[jadrian]

Einsten told us that the speed of light would be measured the same regardless of how fast we were travelling. Is that intuitive? His theories also tell us that a spaceman who travels around the galaxy for a while and returns to Earth will be younger than his twin. That's certainly not intuitive either.

you say "is that intuitive?" intuition isn't the same for all. in fact it is relative lol no pun intended. einsteins thoughts that the speed of light is the same for all observers and the spaceman traveling at high speed will age slower and that space and time were inseparable WERE INTUITIVE to him.

f=ma is not intuitive to a retarded person.

you might ask if we would arrived at relativity today without einsteins intuition.

my guess is yes but its possible we might still not have come to relativity without einstein.

either way, einstein proves how far iq and intuition can take you.

 

[lugita15]

you say "is that intuitive?" intuition isn't the same for all. in fact it is relative lol no pun intended. einsteins thoughts that the speed of light is the same for all observers and the spaceman traveling at high speed will age slower and that space and time were inseparable WERE INTUITIVE to him.

Off topic, but Einstein definitely did not find the new radical notions of space and time he came up with intuitive. He was led to SR because he saw that the electrodynamics of moving bodies seemed to possesses a greater degree of symmetry than their conventional description gave them credit for, and so he tried to redo the laws of kinematics so that Maxwell's equations could be shown to conform with the principle of relativity.

 

[jadrian]

you say "is that intuitive?" intuition isn't the same for all. in fact it is relative lol no pun intended. einsteins thoughts that the speed of light is the same for all observers and the spaceman traveling at high speed will age slower and that space and time were inseparable WERE INTUITIVE to him.

f=ma is not intuitive to a retarded person.

you might ask if we would arrived at relativity today without einsteins intuition.

my guess is yes but its possible we might still not have come to relativity without einstein.

either way, einstein proves how far iq and intuition can take you.

another example, is it intuitive that we are indistingushable from nonliving chemical processes, leading to the conclusion that either we must either regard all chemical reactions as living, or that we are not alive in the traditional sense. i came to this conclusion through my intuition, and simply thinking about it. while kiths intuition apparently was not adequate, i think this conclusion i came to should be intuitive to anybody.

 

[ThomasT]

from my thinking nonlocality and entanglement are never a problem because in a totally determinstic universe, the information about what is going to be instantaneously tranferred from a to b is already known to the universe.

There's no way to know or demonstrate that information, or anything else, is instantaneously transferred from a to b. In fact, instantaneous propagation is a contradiction in terms. If a and b are changing instantaneously, then they're changing simultaneously. And there's nothing in our observations of our world, our universe, that suggests that simultaneous, spacelike separated, changes in a and b imply a causal relationship, or any sort of communication, between a and b. Rather, what this does imply is that a and b are part of a larger system, or that a and b have something in common due to a common cause.

Wrt some formulations (eg., inferred wrt standard QM and explicit wrt dBB interpretation) a and b can be said to change, or are explicitly encoded as changing, simultaneously. So, if one wants to give this some sort of pseudo mechanical meaning, then one might say that information is being instantaneously transferred between a and b. But this isn't really mechanics. It's just an assumption that can't be verified or falsified. Ie., a physically meaningless statement.

... we may not be in block time but the universe acts as if it were.

That's news to me. I would say that observations indicate that our universe behaves contrary to the notion of block time. That is, it's evolving and transitory. But that certain theoretical constructs/eventualities suggest block time. And, afaik, the theoretical stuff that suggests block time (or that contradicts observation) is more or less routinely disregarded/discarded.

... why is [my view] not mainstream?

Because it's unwarranted wrt extant observation and mainstream interpretation of theory.

Your title asks why superdeterminsim isn't universally accepted. My guess is that it's because superdeterminism doesn't refer to anything other than determinism. Determinism might not be universally accepted, but I think it's the predominant assumption and starting point wrt virtually all of the physical sciences.

In this context, superdeterminism is NOT merely the idea that everything is deterministic, i.e., that future is completely determined by the past. If superdeterminism was only that, then it could not avoid nonlocality.

Why not? Are you saying that the assumption of determinism implies action at a distance? Or superluminal propagations?

Instead, superdeterminism is much more. It is the idea that
1. Future is completely determined by the past.

Ok. So far this is just determinism.

AND
2. The past (i.e., initial conditions) is not arbitrary, but is fine tuned so that in the future we see correlations between distant object which never mutually interacted.

You've arbitrarily assumed a starting point (ie., initial conditions) that isn't influenced by past events. But we can just as well assume that wrt whatever you want to assume as a starting point there are antecedent events, ie., some prior history/conditions.

So, as far as I can tell, superdeterminism is a superfluous term, which actually just refers to determinism.

 

[lugita15]

ThomasT, a while back I told you what distinguishes superdeterminism from regular determinism, as well as what time t=0 is:
https://www.physicsforums.com/showthread.php?p=3523407

 

[ThomasT]

ThomasT, a while back I told you what distinguishes superdeterminism from regular determinism ...

Yes, I reread your reply. I still don't understand what differentiates superdeterminism from determinism. I think Demystifier also tried to explain it one time to me. That didn't do it for me either. Or what Bell or 't Hooft have to say about it. I mean, it just isn't clear to me what the word superdeterminism refers to that's different from what the word determinism refers to.

 

[lugita15]

Yes, I reread your reply. I still don't understand what differentiates superdeterminism from determinism. I think Demystifier also tried to explain it one time to me. That didn't do it for me either. Or what Bell or 't Hooft have to say about it. I mean, it just isn't clear to me what the word superdeterminism refers to that's different from what the word determinism refers to.

Superdeterminism equals determinism plus conspiracy. If you take an arbitrary local realist theory with arbitrary initial conditions, it will satisfy Bell's inequality, meaning that it will not display the Bell-type nonlocal correlations necessary to reproduce the predictions of quantum mechanics. In contrast, in a local superdeterministic theory you make all the particles in the universe have some big meeting some time in the past, where they all set the initial states of their hidden variables just right, so that they can all work together in an elaborate conspiracy to make sure that every Bell test performed in the history of the universe will make Bell's inequality appear violated even though it really isn't. In other words, you're making it seems as if local determinism is false even though it is really true. On the other hand, an ordinary local realist theory will easily produce predictions which disagree with quantum mechanics.

 

[DrChinese]

To repeat, in order to have Bell-type nonlocal correlations between A and D in a local deterministic theory, we need A and D not only to have interacted in the past, but to have interacted in just the right way so that they would get the right "conspiratorial" initial conditions so that they would display the right kind of nonlocal correlations years later.

Yes, and to drive home to jadrian a point I keep making: A and D could NEVER have interacted in the past because they NEVER existed in a common light cone. They were "born" too far apart! So now you have to modify the physics so that the lasers that created them (which are pulse matched) must contain the information needed to yield the correlations. But that means it is the pulse that does this (since other lasers won't be able to do this). The pulse doesn't contain enough information to cause that to happen. So now you need even more ad hoc hypotheses to make it all work out.

And this is just one setup.

 

[ThomasT]

Superdeterminism equals determinism plus conspiracy. If you take an arbitrary local realist theory with arbitrary initial conditions, it will satisfy Bell's inequality, meaning that it will not display the Bell-type nonlocal correlations necessary to reproduce the predictions of quantum mechanics.

I'm not sure what you mean by "arbitrary initial conditions". An experimental preparation designed to produce entanglement stats isn't "arbitrary", is it?

In contrast, in a local superdeterministic theory you make all the particles in the universe have some big meeting some time in the past, where they all set the initial states of their hidden variables just right, so that they can all work together in an elaborate conspiracy to make sure that every Bell test performed in the history of the universe will make Bell's inequality appear violated even though it really isn't.

Hmmm. Well, this just seems silly to me. No offense. Maybe you can elaborate on this, explain what you're talking about, in a way that doesn't seem silly?

In other words, you're making it seem as if local determinism is false even though it is really true. On the other hand, an ordinary local realist theory will easily produce predictions which disagree with quantum mechanics.

Like I said, this makes no sense to me. Maybe it's just me. Maybe I'm just extraordinarily dense. I don't know (obviously, I wouldn't). But if so, is there another way that you might present/explain what superdeterminism means that I, and other laymen, might understand? Because what you've written so far doesn't make any sense to me.

How is superdeterminism different from determinism?

Determinism has a pretty simple definition. So, just define superdeterminism. What, exactly, does it refer to (that makes it different from determinism)?

 

[ThomasT]

The pulse doesn't contain enough information to cause that to happen.

To cause what to happen? Entanglement? But entanglement can be created by zapping spatially separated particles with the same pulses, can't it? If so, then apparently the laser pulses do impart enough common info to produce entanglement.

 

[lugita15]

Superdeterminism is a subset of determinism. A
local superdeterministic theory is a local deterministic theory in which the behavior of particles today display Bell-type nonlocal correlation (as opposed to just EPR-type nonlocal correlation) not due to nonlocal interaction today, but due to local interaction in the past. Is that clear enough?

 

[ThomasT]

Superdeterminism is a subset of determinism. A
local superdeterministic theory is a local deterministic theory in which the behavior of particles today display Bell-type nonlocal correlation (as opposed to just EPR-type nonlocal correlation) not due to nonlocal interaction today, but due to local interaction in the past. Is that clear enough?

Ok, thanks. Give me a few minutes to consider this.

EDIT: Ok, I've considered it. A local superdeterministic theory is a local deterministic theory in which the behavior of particles display entanglement correlations due to interaction with each other, or a common origin, or an identical torque applied to both.

This is just determinism. There's nothing, as far as I can tell, super about it.

 

[DrChinese]

To cause what to happen? Entanglement? But entanglement can be created by zapping spatially separated particles with the same pulses, can't it? If so, then apparently the laser pulses do impart enough common info to produce entanglement.

The pulse synchronization IS enough for entanglement. But doesn't impart the information beyond that necessary to maintain the superdeterministic mechanism. After all, the pulse is periodic and there are no other variables to speak of. So it is a pretty small communication channel.

 

[ThomasT]

The pulse synchronization IS enough for entanglement. But doesn't impart the information beyond that necessary to maintain the superdeterministic mechanism. After all, the pulse is periodic and there are no other variables to speak of. So it is a pretty small communication channel.

Thanks for the reply. But you're doing it also. I really don't know what you guys mean by superdeterminism.

 

[jadrian]

OK, let me give you an example of why you need special initial conditions.

In a deterministic theory, in order to predict the current behavior of any object, you need to know the initial conditions of the object, as well as the deterministic laws of the universe. In Newtonian mechanics, for example, you need to know the positions and velocities of all the particles at time t=0, and then F=ma will tell you the behavior of the particles at all later times.

Now let's consider what a local deterministic explanation of entanglement would look like. Let particles A and B be an entangled pair of photons, which are separated by a great distance and then sent through polarization detectors. We also have particles C and D: C tells the experimenter what angle he should set the polarizer that measures A, and D tells the experimenter how to set the polarizer that measures B. You can think of C and D as neurons in the brains of the experimenters if you like.

Now we find experimentally that the behavior of particle A through its measurement device is strongly correlated with the angle at which B's measurement device is set. And that angle is determined by particle D. So we have a correlation between the behavior of particles A and D.

But particles A and D are separated by such a large distance, so they cannot communicate with each other to coordinate their behavior (unless you have a nonlocal theory like Bohmian mechanics which allow undetectable faster-than-light signalling between particles). So a local determinist has to conclude that A and D are correlated not based on a current relationship between the present states of A and D, which would be impossible, but based on a past relationship of the initial states of A and D.

This is what we mean by special initial conditions: A and D seemingly have nothing to do with each other. After all, it is A and B that were in the entangled state, and yet somehow we have to conclude that the initial conditions of A and D had to be specially set so that a correlation between A and D would be observed in the future. And instead of just D, we can have a large number of particles D1, D2, D3,... which together determine the measurement setting, so the initial state of particle A had to have been set based on the initial states of all these particles. And in the real world, almost all particles in the universe are interacting in some way with almost all other particles, so really the setting of measurement device depends on almost everything in the universe, from which we conclude that the initial conditions of the whole universe were specially set so that the right kind of correlation would be displayed billions of years later between particle A and the measuring device.

This is why superdeterminism is called "conspiratorial". That doesn't mean it's wrong, it just has some issues which make it rather difficult to construct a viable superdeterministic theory, but let me repeat that some potential first steps toward such a theory have already been taken by a few people.

By the way i think you should be focusing more on simply c and d which i presume are next to the measurement devices and thus are far apart so they are the "conspirators", because they causally effect the outcome of the measurements by bumping the measurement device into whatever angle. either way a and d or c and d doesn't matter which you consider to be conspiring. There should be nothing conspiratorial about particle d being able to affect particle c and therefore effect a because in the history of the universe, the 10^10^MILLION (who can say how many?) interactions that have taken place, through causality and info exchange, HAVE PREDETERMINED that particle d was going to effect c and therefore a. you say a and d seemingly have nothing to do with each other. THEY HAVE EVERYTHING TO DO WITH EACHOTHER! Simple logical determinism would lead you to the conclusion that d had causal effects on perhaps everything in the universe which ultimately led to the causal outcome of the measurement of a. Not only that but particle d,d1,d2,d3 d infinity not only via cause-effect cause-effect cause-effect...eventually caused c to affect the measurement device for a, but d, d1, d2... caused the experimenters to make the experiment take place in the first place.

i don't believe faster than light info transfer will be an issue here as it is not an issue with normal entanglement, because info transferred at the speed of light will always beat instantaneous info transfer to the punch. Sending light in opposite directions i suspect would be solvable by relativity to give the same conclusion.

dont think of it not particles all knowing about each other, think of it as historical interactions in the universe as spreading a virus to every particle in the entire universe.

its not that every particle knows everything about every other particle. it only knows what has happened to it in the past. but the addition of all current states of particles which are in their current state because of their continuous past history traced back in time will give you the full information in the universe, and having this information, you would be able to predict it. and if you could predict it, that would mean it must be deterministic as a whole. so although we cannot predict the future, and the future isn't predictable, que sera' sera'.

 

[lugita15]

Ok, thanks. Give me a few minutes to consider this.

EDIT: Ok, I've considered it. A local superdeterministic theory is a local deterministic theory in which the behavior of particles display entanglement correlations due to interaction with each other, or a common origin, or an identical torque applied to both.

This is just determinism. There's nothing, as far as I can tell, super about it.

An ordinary local realist theory can only produce EPR-type nonlocal correlations, but in order to produce Bell-type nonlocal correlations you require a local superdeterministic theory. Referring to Nick Herbert's explanation here [PLAIN]http://quantumtantra.com/bell2.html,[/PLAIN] the fact that entangled photons do the same thing when going through polarizers oriented at 0 degrees is an example of an EPR-type nonlocal correlation; a local realist can easily explain it by saying that the photons agreed in advance whether they should go through or not go through a 0 degree polarizer. An example of a Bell-type nonlocal correlation is the fact that the mismatch at 60 degrees is more than twice the mismatch at 30 degrees.

To explain such a correlation requires not just that the photons interacted some time in the past, but it also requires that some time in the past the photons interacted with whatever is controlling the polarizer setting (and that could be anything: neurons in the brains of the experimenters, coin flips, dice rolls, the weather in Houston... a wacky experimenter can set the polarizer angles based on just about anything)

So here's another way to put it: An ordinary local realist theory just assumes that particles which are considered entangled according to QM must have had local interactions in the past which is determining their EPR-type nonlocal correlations today. But a local superdeterminist theory assumes that a particle must have interacted in the past with not only those that are entangled with it according to quantum mechanics, but also other particles which quantum mechanics would say have no connection with it. This is how a local superdeterministic theory would be able to produce Bell-type nonlocal correlations.

 

[DrChinese]

Thanks for the reply. But you're doing it also. I really don't know what you guys mean by superdeterminism.

The superdeterminism part is simple: it is the new particle properties and physical interactions which need to be added to explain Bell test results. This cannot be done with known currently physical processes within a local realistic setting.

 

[lugita15]

By the way i think you should be focusing more on simply c and d which i presume are next to the measurement devices and thus are far apart so they are the "conspirators", because they causally effect the outcome of the measurements by bumping the measurement device into whatever angle. either way a and d or c and d doesn't matter which you consider to be conspiring. There should be nothing conspiratorial about particle d being able to affect particle c and therefore effect a because in the history of the universe, the 10^10^MILLION (who can say how many?) interactions that have taken place, through causality and info exchange, HAVE PREDETERMINED that particle d was going to effect c and therefore a. you say a and d seemingly have nothing to do with each other. THEY HAVE EVERYTHING TO DO WITH EACHOTHER! Simple logical determinism would lead you to the conclusion that d had causal effects on perhaps everything in the universe which ultimately led to the causal outcome of the measurement of a. Not only that but particle d,d1,d2,d3 d infinity not only via cause-effect cause-effect cause-effect...eventually caused c to affect the measurement device for a, but d, d1, d2... caused the experimenters to make the experiment take place in the first place.

Actually, we find experimentally that A has a nonlocal correlation with D, but C does not have any correlation with D. So what you're saying doesn't make much sense.

i don't believe faster than light info transfer will be an issue here as it is not an issue with normal entanglement, because info transferred at the speed of light will always beat instantaneous info transfer to the punch. Sending light in opposite directions i suspect would be solvable by relativity to give the same conclusion.

I'm not sure what you're talking about. Obviously the speed of light is finite, so if there were such a thing as instantaneous information transfer then light wouldn't be able to beat it.

dont think of it not particles all knowing about each other, think of it as historical interactions in the universe as spreading a virus to every particle in the entire universe.

its not that every particle knows everything about every other particle. it only knows what has happened to it in the past. but the addition of all current states of particles which are in their current state because of their continuous past history traced back in time will give you the full information in the universe, and having this information, you would be able to predict it. and if you could predict it, that would mean it must be deterministic as a whole. so although we cannot predict the future, and the future isn't predictable, que sera' sera'.

I've told you this several times already, but the conspiratorial part is NOT the mere fact that all the particles in the universe (or their ancestors) interacted in some way or another with each other at some point in the past. The conspiratorial part is that they used the information derived from this interaction to set their initial states in just the right way so as to produce a Bell-type nonlocal correlation. There's lots of possible interactions particles can have; how did they have just the right kind of interaction so that they would get the right kind of initial states? That's what a superdeterministic theory would have to explain if it didn't want to be considered ad hoc.

 

[DrChinese]

...its not that every particle knows everything about every other particle. it only knows what has happened to it in the past. but the addition of all current states of particles which are in their current state because of their continuous past history traced back in time will give you the full information in the universe, and having this information, you would be able to predict it. ...

There is not a scintilla of evidence this is so. Do you not see that you are making up the physics as you go along? This is why I refer to superdeterminism as "ad hoc".

Please note that photons A and D only exist for a short period of time, and have never been in contact with each others' light cones. Yet they are entangled. That entanglement can be made to occur AFTER they cease to exist. (Yes you read this correctly.)

See page 5 especially:
http://arxiv.org/abs/quant-ph/0201134

So none of that is contemplated by your version of superdeterminism. Since by your definition, causes must precede effects. Obviously, if I choose to entangle particles that no longer exist, then I am changing the past (which I am in quantum terms).

And if I am correct, in that you are creating an ad hoc theory, I am sure a modification will be forthcoming in an attempt to keep the idea going. Or perhaps you will say uncle, and realize that some additional research on quantum theory would be beneficial to you. There is a lot of fascinating stuff out there!

By the way, we have all been down similar roads at one point or another. No one is picking on you, and we are not foolishly pro free will. I really don't care if there is free will or not, I still have to make the same decisions every morning either way.

 

[kith]

Maybe we should consider another point of view on the "conspiracy".

I'm not sure, if this wording is really a good choice. Seemingly very special initial conditions in other areas are well-known, consider the problem of finetuning. So maybe the "conspiracy" is analogous to the situation there.

If the universe started in a very dense state, it seems probable, that all particles are correlated. And since quantum mechanics is necessary to explain the stability of atoms, the special choice of initial conditions could be explainable by the anthropic principle: a world with only classical correlations would not support life.

 

[lugita15]

Obviously, if I choose to entangle particles that no longer exist, then I am changing the past (which I am in quantum terms).

That characterization of delayed choice experiments is a controversial one that's not agreed on by everyone. In fact, I think there was an old thread where Demystifier set out to show that almost no major interpretation of quantum mechanics would actually interpret delayed choice as changing the past. But yes, I agree that delayed choice poses some thorny issues for deterministic theories.

 

[lugita15]

And since quantum mechanics is necessary to explain the stability of atoms, the special choice of initial conditions could be explainable by the anthropic principle: a world with only classical correlations would not support life.

Entanglement seems to be a relatively rare phenomenon (does it occur in nature at all, except with some nonlinear crystals?), so how important could nonlocal correlations be to life?

 

[DrChinese]

That characterization of delayed choice experiments is a controversial one that's not agreed on by everyone. In fact, I think there was an old thread where Demystifier set out to show that almost no major interpretation of quantum mechanics would actually interpret delayed choice as changing the past. But yes, I agree that delayed choice poses some thorny issues for deterministic theories.

I referred to it in the quantum sense of temporal order, just as you might refer to quantum non-locality. Quantum non-locality is not the same as having physically non-local forces. Of course there are interpretations, such as Bohmiam which we already mentioned, that do not involve retrocausality and in fact are deterministic.

On the other hand, I consider any interpretation in which there are elements of time symmetry or block structure to be retrocausal. The point is, time exhibits a degree of freedom. Any way you look at it, in the experiment cited, the decision to entangle is made after the entangled pair is detected. So whatever you choose to call that, it isn't viable under superdeterminism UNLESS jadrian postulates ever more and more new and exotic features to our universe. Which is I think what we are both saying, the ad hoc nature of the theory never ceases to grow.

 

[DrChinese]

Seemingly very special initial conditions in other areas are well-known, consider the problem of finetuning. So maybe the "conspiracy" is analogous to the situation there.

If the universe started in a very dense state, it seems probable, that all particles are correlated. And since quantum mechanics is necessary to explain the stability of atoms, the special choice of initial conditions could be explainable by the anthropic principle: a world with only classical correlations would not support life.

The reason this is not possible is: there are NO initial conditions that lead to these results! That is the point, you must add new and otherwise hidden physical laws to account for the results. And they can't just be hidden variables, as Bell showed.

No, you must now add physics which explains the experimenter's choice of measurement directions as being part of everything, i.e. themselves part of the initial conditions AND causally connected to the results themselves. We don't have anything in current theory that does that. So you have to make it up as you go along.

So as I devise new and more devious Bell test setups (all perfectly viable), you have to invent new physics.

As to the possibility that all the particles in the universe are correlated or entangled: that is perfectly reasonable. In fact, I would venture a wild guess that the total spin of the universe is precisely zero. That would make everything entangled in some small way. However, that piece of information is worthless when looking at any particular subset of particles, which could have any total spin value. So the point is that the initial condition of zero total spin (or any other value) does NOT in any way explain correlations between particular pairs of particles.

So I wouldn't recommend initial conditions as an explanation of Bell test results, you need particular physics too.

 

[kith]

Entanglement seems to be a relatively rare phenomenon (does it occur in nature at all, except with some nonlinear crystals?)

Entanglement as such is not rare. Most decay processes yield entangled particles. In principle, all fermionic states are entangled (because of their antisymmetry). Also most open systems are entangled with their environment. As DrC points out, it seems more like entanglement is the standard thing.

The reason that it is rarely present in experiments, is that we either don't want to keep track of it (because we are interested in analyzing the properties of single particles), or that we are not able to keep track of it (because we don't have direct access to the other particles). So most experiments are simply missing Bob.

so how important could nonlocal correlations be to life?

Quantum mechanics may be important for life (because classical atoms are not stable). Nonlocal correlations have not to be directly related to this. They may be just another consequence of the structure of quantum mechanics.

 

[kith]

The reason this is not possible is: there are NO initial conditions that lead to these results!

If superdeterminism is a valid point of view, then initial conditions determine everything. Of course, they can be initial conditions of some unknown superdeterministic laws and need not have to be initial conditions of orthodox quantum mechanics.

My criticism was the wording "conspirational", which seems to refer to the following situation: in the beginning of the universe, all degrees of freedom (of our possibly superdeterministic laws) have conspired to make future experimenters make choices in such a way that the universe looks nonlocal to them, while in truth it isn't. If the initial conditions had been less improbable ("non-conspirational"), the universe would be classical.

So if people use this argument to criticize superdeterminsm, one can reply by the anthropic principle: in these non-conspirational, classical universes, atoms would be unstable and life would not exist.

That is the point, you must add new and otherwise hidden physical laws to account for the results. And they can't just be hidden variables, as Bell showed.

Didn't Bell himself say the contrary in his famous superdeterminism quote? His theorem shows that no local realistic theory can reproduce all predictions of quantum mechanics under the assumption of free choice of the observables to be measured (please object if you think this is wrong).