Register to reply

Why is superdeterminism not the universally accepted explanation of nonlocality?

Share this thread:
jadrian
#73
Feb26-12, 10:51 PM
P: 143
[QUOTE=lugita15;3785784]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
#74
Feb26-12, 11:05 PM
P: 1,583
Quote Quote by jadrian View Post
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
#75
Feb26-12, 11:19 PM
P: 143
Quote Quote by Joncon View Post
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 isnt 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
#76
Feb26-12, 11:27 PM
P: 1,583
Quote Quote by jadrian View Post
you say "is that intuitive?" intuition isnt 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 possess 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
#77
Feb26-12, 11:28 PM
P: 143
Quote Quote by jadrian View Post
you say "is that intuitive?" intuition isnt 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
#78
Feb27-12, 01:43 AM
P: 1,414
Quote Quote by jadrian View Post
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.

Quote Quote by jadrian View Post
... 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.

Quote Quote by jadrian View Post
... 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.

Quote Quote by Demystifier
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?

Quote Quote by Demystifier
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.

Quote Quote by Demystifier
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
#79
Feb27-12, 03:12 AM
P: 1,583
ThomasT, a while back I told you what distinguishes superdeterminism from regular determinism, as well as what time t=0 is:
http://www.physicsforums.com/showthread.php?p=3523407
ThomasT
#80
Feb27-12, 03:19 AM
P: 1,414
Quote Quote by lugita15 View Post
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
#81
Feb27-12, 08:51 AM
P: 1,583
Quote Quote by ThomasT View Post
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
#82
Feb27-12, 09:09 AM
Sci Advisor
PF Gold
DrChinese's Avatar
P: 5,385
Quote Quote by lugita15 View Post
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
#83
Feb27-12, 09:45 AM
P: 1,414
Quote Quote by lugita15 View Post
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?

Quote Quote by lugita15 View Post
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?

Quote Quote by lugita15 View Post
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
#84
Feb27-12, 09:56 AM
P: 1,414
Quote Quote by DrChinese View Post
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
#85
Feb27-12, 10:01 AM
P: 1,583
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
#86
Feb27-12, 10:02 AM
P: 1,414
Quote Quote by lugita15 View Post
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
#87
Feb27-12, 12:36 PM
Sci Advisor
PF Gold
DrChinese's Avatar
P: 5,385
Quote Quote by ThomasT View Post
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
#88
Feb27-12, 12:43 PM
P: 1,414
Quote Quote by DrChinese View Post
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
#89
Feb27-12, 01:07 PM
P: 143
Quote Quote by lugita15 View Post
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 seperated 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 doesnt 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 eachother. 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 dont believe faster than light info transfer will be an issue here as it is not an issue with normal entanglement, because info transfered 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 eachother, 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 isnt predictable, que sera' sera'.
lugita15
#90
Feb27-12, 01:38 PM
P: 1,583
Quote Quote by ThomasT View Post
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 , 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.


Register to reply

Related Discussions
Gauss' Law Universally True? Classical Physics 36
Superluminal instantaneous influence Quantum Physics 5
Arguments Against Superdeterminism General Discussion 142
Why is there such little talk regarding superdeterminism? General Discussion 23
I hear a lot about nonlocality and it's relationship to QM Quantum Physics 3