EPR experiments imply STR not correct?

[zenith8]

It's almost as if a MWI adherent was arguing that not only do parallel realities exist, but that it must also be physically possible to communicate between these realities, and the fact that no advanced parallel civilisation has done so to date proves that evolution is false and the multiverse has only existed for 10,000 years.

It isn't in the least like that. You just wrote that because it sounds cool (if anyone lurking in these forums can ever said to be so).

Even if Bohmian mechanics were true (despite it being otherwise demonstrated less fruitful to date), and even if the existence of non-equilibrium states does permit instantaneous messaging (which I'll take as given), and even if an absolute reference frame was the physically preferred way to mitigate paradoxes in such a situation (rather than an obvious alternative such as the block-universe which is consistent with modern GR), Zenith has still forgotten to give strong evidence for the extraordinary claim that nonequillibrium matter can actually exist.

Given your first three ifs to be true - as you state - then in reality it would be a more extraordinary claim - indeed a fantastical one - to suggest that nonequilibrium matter cannot exist. Hidden variables theories of this nature are nothing other than a statistical mechanics of waves and particles, with particular underlying laws of dynamics (which differ from the classical ones). No one goes around saying that it is impossible for classical particles to not be distributed according to the Boltzmann distribution. Why on Earth would you say the same in the quantum case? Baffling.

Zenith

 

[Mentz114]

Zenith,
If we could we use the instantaneous signalling to broadcast a universal absolute time signal, this would enable anyone to detect their absolute motion ( ie wrt the preferred frame) by comparing their clock rate to the absolute clock. So another cornerstone of relativity is undermined by instantaneous transmission.

Also please explain soberly why an absolute clock or reference frame would prevent observers seeing contradictory outcomes ? The contradictions are not because of the particular ST model, but the instantaneity.

In spite of your triumphal tone and supercilious remarks - you have not made your case.

M

 

[zenith8]

Zenith,
If we could we use the instantaneous signalling to broadcast a universal absolute time signal, this would enable anyone to detect their absolute motion ( ie wrt the preferred frame) by comparing their clock rate to the absolute clock. So another cornerstone of relativity is undermined by instantaneous transmission.

Indeed. And the existence of nonlocality does undermine the epistemological and ontological basis of STR, as you state. You're beginning to sound like a Lorentzian.

Also please explain soberly why an absolute clock or reference frame would prevent observers seeing contradictory outcomes ? The contradictions are not because of the particular ST model, but the instantaneity.

OK. The backwards in time paradoxes indeed require the structure of spacetime to be Minkowskian (as we have seen with your spaceship).

If instead we have a given preferred frame with standard Lorentzian global coordinates x,y,z,t instantaneous signalling between distant spaceships would not in itself be problematic in that frame. But what about the Lorentz transformation? You migh be disturbed by the idea that by moving along the x-axis you could 'see' such signals propagating 'backwards in time'. But in reality you are not 'seeing' the global time of the Lorentz frame. Rather, you have a collection of clocks distributed over space, and these have to be *set* according to some procedure. The time associated with an event occurring at some point in space is just the reading of the clock in the neighbourhood of that event. If an event B is for some physical reason regarded as 'causing' a spatially distant event A (e.g. a message is sent from B to A) and if the reading of a clock at B is larger than the reading of a clock at A, then before declaring this paradoxical you ought to ask how the clocks at A and B were set in the first place.

If you choose Einstein's so-called 'synchronization' using light pulses whose speed is taken to be isotropic, then at (global) time t the moving clock located at x,y,z, will read a time t' = t-vc/x^2 / sqrt(1-v^2/c2). The interpretation of this formula is simple. The moving clocks distributed along x>0 have been initially set to read progressively earier times, with a lag proportional to x; while the moving clocks along x<0 have been similarly set to read later times.

These settings have been chosen precisely so as to make a light pulse (with speed c in the global frame) appear to have a speed c, along both +x and -x in the moving frame. This is the origin of the term -vx/c^2 (to lowest order in v/c). If you include the effect of motion which slows clocks down you also get the fact 1/sqrt(1-v^2/c^2).

With this convention we have the following peculiarity: an instantaneous signal propagating along x in the global frame appears to be going 'backwards in time' as judged by the moving clocks with settings t'.
However, this is *not* mysterious or paradoxical. It is exactly the same as "jet lag" if you're on a flight round the world. Clocks on the Earth's surface have been set according to a convention based on the locally observed position of the Sun in the sky, and it is no way surprising that an airplane passenger can formally 'travel backwards in time' with respect to them.

That's the difference.

In spite of your triumphal tone and supercilious remarks - you have not made your case.

If you say so..

Zenith.

 

[zenith8]

I have no issue with anything you wrote, except the following:

Of course Lorentz and Einstein have different ontologies. But ontologies are not experimentally testable. The only thing that is accessible to experimental evidence is the result of measurements, on which point Lorentz and Einstein agree entirely. The Lorentzian aether is, by design, not experimentally measureable, it is, by design, an undetectable ontological entity.

Again, I don't care if you prefer Lorentz over Einstein, but there is no experimental evidence to justify that preference. There is also no experimental evidence to refute that preference either. They are not really different theories, but only different interpertations of the Lorentz transforms.

Ontologies are experimentally testable.

It is completely obvious that one can have experimental evidence which disproves an ontological or epistemological supposition. The ontology for a given theory is simply a statement of what is supposed to be real or to 'exist' in that theory (it has nothing to do with whatever is the ultimate reality in the real universe, which there is no way of knowing for certain, as we may be in the Matrix, and of course our theory is almost certainly not the Final Theory of Everything).

For instance if am a fourteenth-century astronomer I may posit as my astrophysical ontology that the Moon and all other heavenly bodies are made of cheese. There was no way at the time anyone could prove me wrong, so in time the Zenith Cheese Theory became big news. Now they may beg to differ.

Relativity is an excellent example of this. If someone turns out to be discover experimental evidence for a preferred frame, then Einsteinian STR - which says that there is no such frame and all frames are equivalent - will have been falsified. One might choose then to replace Einsteinian STR with Lorentzian relativity which *is* compatible with a preferred frame - but you are claiming this differs in no way that is testable from Einstein, which is surely not correct. The nonlocality people are claiming that they have found evidence for such a preferred frame - you need to be arguing with them, not about semantics..

Zenith

 

[Mentz114]

Zenith,

OK. The backwards in time paradoxes indeed require the structure of spacetime to be Minkowskian (as we have seen with your spaceship).

That example doesn't rule out paradoxes in different models of spacetime. Just because one thing is square doesn't mean something else can't be. I assert that the paradoxes are caused by instantaneous transmission.

But what about the Lorentz transformation?

What indeed. Are you saying that the LT also fits between observers in Lorentz relativity ? If so, obviously the same paradoxes could be arranged.

The rest of what you've written doesn't seem to address the issue.

Indeed. And the existence of nonlocality does undermine the epistemological and ontological basis of STR, as you state. You're beginning to sound like a Lorentzian.

Nonsense. I reject your ideas. You are prejudging the way nature works because you have an agenda, and you think the vague kind of non-locality arguments help you with it. I doubt if any kind of signalling as we think of it occurs in the quantum non-local phenomena. They can more easily be explained by using some small dimensions, which is a lot more believable than your interpretation with it's emphasis on absolutism, and impossible instantaneous transmission.

There's a lot more out there than in your philosophy, Zenith.

 

[Fredrik]

The implication of possible non-local signalling occurs in all deterministic hidden variables theories - as has been well known for 20 years. A clear proof is given in the Valentini article in the recent book 'Einstein, Relativity and Absolute Simultaneity" p. 137 - available on Google Books,

Page 137 mentions "instantaneous signaling at the statistical level", not "instantaneous messages". What makes you interpret what they're saying as a claim that you can send instantaneous messages this way? As far as I can tell (after only skimming it), they do not claim that you can send even a single bit of information this way, at least not on pages 137-138. (Pages 139-140 aren't included in the preview).

Given that a coherent proposal entirely consistent with the mathematics of standard QM for instantaneous signalling *exists*, then let us *assume* it can be done in the way suggested, and examine the consequences of this for spacetime structure.That's all I'm asking.

That doesn't make any sense. The "given" part is false, and you haven't suggested any way to send those messages, so the words "in the way suggested" refer to something undefined.

You've been doing more than asking that. You've been claiming not only that QM implies absolute simultaneity (because of EPR), but also that you have already proved that claim in this thread. Both of those claims are false.

For that purpose it's irrelevant whether the signalling is technically feasible in an engineering sense, or whether the Bohmian interpretation has anything to do with reality

I agree 100% (and I don't think I've given you a reason to believe that I wouldn't agree with this). It is however extremely relevant if you can come up with a thought experiment in which a single-bit message can be sent and received at events with spacelike separation. In fact, that would be the only way to prove your claim.

MWI right?

I don't have a favorite interpretation. Actually I think almost everything that's ever been said about interpretations of the standard formulation of QM is irrelevant nonsense. I don't think we should be talking about "interpretations" at all. I think we should be talking about a set of theories that may or may not be equivalent. (I'd like to define two theories to be "mathematically equivalent" if the axioms of either theory can be derived from the axioms of the other, and "physically equivalent" if they make the same predictions about the results of experiments). I will only be able to take the MWI seriously if I see a list of statements that defines it in a way that makes it a theory according to my definition of "theory". I know very little about Bohm, but the impression I have is that it can be expressed in the form of a "theory", so I'm less skeptical of Bohm than of the MWI.

My definition of "theory"? Short version: A set of unambiguous statements that tell us how to calculate probabilities of logically possible results of experiments. The set must also be finite, logically consistent, and not contain any statements that can be removed without changing or removing some of the predictions about the probabilities.

 

[Dale]

Ontologies are experimentally testable.

No they are not. Only predictions of measurements are experimentally testable. If think you have developed an ontologometer in your garage then you should start manufacturing and selling them. Nobody else has one so you will corner the entire market.

If someone turns out to be discover experimental evidence for a preferred frame, then Einsteinian STR - which says that there is no such frame and all frames are equivalent - will have been falsified. One might choose then to replace Einsteinian STR with Lorentzian relativity which *is* compatible with a preferred frame - but you are claiming this differs in no way that is testable from Einstein, which is surely not correct.

Again, you are not understanding science and logic. Lorentz is not compatible with just any arbitrary preferred frame, it must work according to the Lorentz transform. Lorentz is thus only compatible with an experimentally undetectable aether. Therefore, if you do find experimental evidence of a preferred frame then you will have falsified both Einstein (who says there is no preferred frame) and Lorentz (who says it is experimentally undetectable). Again, Lorentz and Einstein both use the same Lorentz transform to make all of their experimental predictions so any experimental result that falsifies one will necessarily falsify the other.

 

[zenith8]

Here's an article published yesterday that is relevant to this discussion.

http://www.sciam.com/article.cfm?id=was-einstein-wrong-about-relativity&print=true"

Zenith

 

[Dale]

First, Scientific American is a popular magazine, not a peer-reviewed journal (not even on the minimal level of arXiv), so take it for what it is. Second, nothing in that article contradicts my point that Lorentz's aether theory and Einstein's special relativity are completely experimentally indistinguishable, nor does anything in the article support your assertion that EPR provides experimental evidence that verifies Lorentz and falsifies Einstein.

You simply cannot make such a choice based on experimental evidence. It is a purely philosophical choice, one which most people have made on the basis of Occham's razor, but one which you are free to make on any aestetic or philosophical basis you like.

 

[zenith8]

First, Scientific American is a popular magazine, not a peer-reviewed journal (not even on the minimal level of arXiv), so take it for what it is. Second, nothing in that article contradicts my point that Lorentz's aether theory and Einstein's special relativity are completely experimentally indistinguishable, nor does anything in the article support your assertion that EPR provides experimental evidence that verifies Lorentz and falsifies Einstein.

You simply cannot make such a choice based on experimental evidence. It is a purely philosophical choice, one which most people have made on the basis of Occham's razor, but one which you are free to make on any aestetic or philosophical basis you like.

Lighten up, Dale. I never said it was a peer-reviewed journal - I just meant to imply it was an interesting, relevant article for the point under discussion. Anyway, David Albert is hardly some undergraduate nutjob - he is widely known as an expert in quantum foundations and has written highly-praised books on the subject.

Try the recent book "Einstein, Relativity, and Absolutely Simultaneity" which contains about 20 articles making the same point. Or is the case of two experts in the field asking 18 other experts in the field to write articles, reading them carefully and criticising them, and publishing them in a book not peer-reviewed enough for you?

Therefore, if you do find experimental evidence of a preferred frame then you will have falsified both Einstein (who says there is no preferred frame) and Lorentz (who says it is experimentally undetectable).

I'm sorry - your argument is logically ludicrous. Lorentz's theory states that there is a preferred frame/ether and explains why that preferred frame/ether would be undetectable in something like a Michelson-Morley experiment relying on measurements of lengths etc.. It does not state or imply that it is impossible to detect the preferred frame at all ever - especially through a completely different (and in 1905 completely unsuspected) mechanism.

Zenith

 

[Mentz114]

Hi Zenit,

interesting article. I noted

Thus, the mere existence of a nonlocality in quantum mechanics, in and of itself, does not mean that quantum mechanics cannot coexist with special relativity. So perhaps there is hope.

Yay ! We're off the hook.

The kind of nonlocality one encounters in quantum mechanics seems to call for an absolute simultaneity, which would pose a very real and ominous threat to special relativity.

( my bold )

Which is not the case surely ? Why does the transmission have to be instantaneous rather than say 100000c ? Notice they say 'seems to'.

The article is a bit woolly in places. It reminded of your posts.

 

[zenith8]

Yay ! We're off the hook.

Damn! [gnashes teeth]

Which is not the case surely ? Why does the transmission have to be instantaneous rather than say 100000c ?

Because that is what QM predicts.

But anyway if it wasn't instantaneous then you would be able to detect the preferred frame. Do an EPR experiment in which the relative time of detection of the two particles was extremely accurately determined. In principle the Bell inequality would then no longer be violated as there wouldn't be any time for the disturbance of one particle to propagate to the other before the measurement was made on it. And then the second particle wouldn't go into the usual state of correlation with the first one. Clearly this would need to be done a lot more accurately than they currently do it (and I think, like Michelson-Morley, you would have to take into account the speed of the Earth through the ether).

And if you did find such a thing that would mean both QM and STR were wrong..!

And then the 'self-appointed defenders of the orthodoxy' (20 points on the http://math.ucr.edu/home/baez/crackpot.html" !) would be really upset..

Notice they say 'seems to'.

Because of the four implausible get-outs I offered in my original post.

Zenith

 

[Mentz114]

I hope you don't include me in the 'defenders of the orthodoxy'. They wouldn't like it.

Probably none our current physical theories are right, but if I have to choose between instant signalling and SR I go with SR on the balance of the evidence.

I'm not convinced that non-locality can be used to propagate messages instantly. The only practical use seems to be ensuring messages have not been read by eavesdroppers.

Because of the four implausible get-outs I offered in my original post

That list is far from complete.

 

[Demystifier]

It seems to me that Bell's theorem and the Aspect EPR-style experiments demonstrating non-locality in quantum mechanics imply an absolute simultaneity and therefore that there must be a preferred frame. The experimentally confirmed instantaneous action at a distance cannot occur otherwise (the actual results of the experiment would be observer dependent if there were no such frame).

Relativity can be made compatible with the existence of a preferred frame if that frame is determined DYNAMICALLY, essentially by the choice of initial conditions. But the initial conditions on what? A possible answer is - the initial conditions on particle 4-positions in a relativistic-covariant version of the Bohmian hidden variable formulation of quantum mechanics.
See e.g.
http://xxx.lanl.gov/abs/quant-ph/0512065 [AIP Conf.Proc.844:272-280,2006]
http://xxx.lanl.gov/abs/0811.1905 [accepted for publication in Int. J. Quantum Inf.]

 

[Fredrik]

I'm sorry - your argument is logically ludicrous. Lorentz's theory states that there is a preferred frame/ether and explains why that preferred frame/ether would be undetectable in something like a Michelson-Morley experiment relying on measurements of lengths etc.. It does not state or imply that it is impossible to detect the preferred frame at all ever - especially through a completely different (and in 1905 completely unsuspected) mechanism.

If the theories make the same predictions about the results of experiments, then it's impossible to distinguish between them. As far as I know, they do make the same predictions. (I could be wrong though; I don't know much about the Lorentz theory). So if an experiment can show that there's a "preferred frame", it proves the Lorentz theory wrong too.

Notice they say 'seems to'.

Because of the four implausible get-outs I offered in my original post.

Those "get-outs" are mostly crazy talk anyway (see #9), but a modified version of #2 is likely the correct answer.

What you really should notice is that they didn't offer any arguments to support the idea that quantum non-locality might require a preferred frame. The article is actually rather strange. The "seems to" comment, and phrases like "hope for special relativity?" and "nonlocality could be compatible with special relativity" suggest there's a good reason to believe that it isn't. And yet they don't mention any such reasons.

 

[Dale]

I'm sorry - your argument is logically ludicrous. Lorentz's theory states that there is a preferred frame/ether and explains why that preferred frame/ether would be undetectable in something like a Michelson-Morley experiment relying on measurements of lengths etc.. It does not state or imply that it is impossible to detect the preferred frame at all ever - especially through a completely different (and in 1905 completely unsuspected) mechanism.

I think I understand the core problem in both this thread and your other thread. You simply do not understand what Lorentz's theory actually says and are supporting it purely out of ignorance. In the last thread you thought that Lorentz predicted physiological or optical "squishing", and in this thread you think that Lorentz is compatible with a detectable preferred frame. In both threads you mistakenly think that any preferred frame will do to support Lorentz, and neglect the fact that it must satisfy the Lorentz transform.

Tell me how you think your EPR experiment both satisfies the Lorentz transform and establishes a preferred frame.

 

[Mentz114]

Instantaneous paradox

If I had some of these instantaneous transceivers, I could arrange them so transmitter A sends to transmitter B, which then sends back to A. A is a bomb also and is triggered by any incoming signal. It explodes at the very same instant it transmits the signal that exploded it.

To be paradoxical this requires absolute simultaneity. Any delay in any part makes it just a stupid bomb.

This is why I distrust absolute concepts.

 

[zenith8]

If I had some of these instantaneous transceivers, I could arrange them so transmitter A sends to transmitter B, which then sends back to A. A is a bomb also and is triggered by any incoming signal. It explodes at the very same instant it transmits the signal that exploded it.

To be paradoxical this requires absolute simultaneity. Any delay in any part makes it just a stupid bomb.

This is why I distrust absolute concepts.

Why don't you just cut out B altogether and just have the big red button on A linked to its own detonator? Same result. The bomb explodes when you press the button. Why is this paradoxical?

 

[Mentz114]

Why don't you just cut out B altogether and just have the big red button on A linked to its own detonator? Same result. The bomb explodes when you press the button. Why is this paradoxical?

Two things happen at the same time and the same place - a signal is sent and destruction of the transmitter takes place. If the events are truly simultaneous we can say that the bomb exploded before the signal was sent with the same validity as the other way round.

Clearly we'll need an experiment to decide what really happens.

 

[zenith8]

Two things happen at the same time and the same place - a signal is sent and destruction of the transmitter takes place. If the events are truly simultaneous we can say that the bomb exploded before the signal was sent with the same validity as the other way round.

Clearly we'll need an experiment to decide what really happens.

No, come on. Most of your comments have been very sensible but you're really off-beam here.

In a real bomb the electrons will take some nanoseconds to traverse the relevant wires to explode the bomb.
If what you are suggesting is true then it is exactly the same paradox when you only have one single device with the red button attached to the detonator. What you're saying is that in your magic bomb it explodes instantaneously as soon as someone presses the button therefore they couldn't possible have pressed it in the first place (which is not true, anyway).

There is no additional content to this though experiment if the signal from the red button takes an instantaneous round trip to the other side of the universe and back, before passing down the wires to the detonator, even if the time from button press to explosion could be shrunk to zero.

Zenith

 

[Demystifier]

Has anybody noticed my post #84?

 

[Mentz114]

No, come on. Most of your comments have been very sensible but you're really off-beam here.

In a real bomb the electrons will take some nanoseconds to traverse the relevant wires to explode the bomb.
If what you are suggesting is true then it is exactly the same paradox when you only have one single device with the red button attached to the detonator. What you're saying is that in your magic bomb it explodes instantaneously as soon as someone presses the button therefore they couldn't possible have pressed it in the first place (which is not true, anyway).

There is no additional content to this though experiment if the signal from the red button takes an instantaneous round trip to the other side of the universe and back, before passing down the wires to the detonator, even if the time from button press to explosion could be shrunk to zero.

Zenith

I suppose the round trip is superfluous. The instant bomb is another kind of paradoxical thing ( it is paradoxical because it both does, and does not explode ).

I will look at Dr Nikolic's papers now. The second one looks interesting - here is the abstract

The kinematic time operator can be naturally defined in relativistic and nonrelativistic quantum mechanics (QM) by treating time on an equal footing with space. The spacetime-position operator acts in the Hilbert space of functions of space and time. Dynamics, however, makes eigenstates of the time operator unphysical. This poses a problem for the standard interpretation of QM and reinforces the role of alternative interpretations such as the Bohmian one. The Bohmian interpretation, despite of being nonlocal in accordance with the Bell theorem, is shown to be relativistic covariant.

 

[zenith8]

I suppose the round trip is superfluous. The instant bomb is another kind of paradoxical thing ( it is paradoxical because it both does, and does not explode ).

Look, I'm sorry - it really is not paradoxical.

You press the red button. The bomb explodes immediately. You die. End of story.

I think you're saying - in effect - that it is not possible for an effect to happen at the same instant as its cause?
Isn't that the definition of locality?

Zenith

 

[Mentz114]

Look, I'm sorry - it really is not paradoxical.

You press the red button. The bomb explodes immediately. You die. End of story.

I think you're saying - in effect - that it is not possible for an effect to happen at the same instant as its cause?
Isn't that the definition of locality?

Zenith

We're talking about two different bombs. As you've pointed out this is not relevant to the issue so let's forget the instant bomb and I'll stop trying to find logical or causal fallacies ( I'm not saying they don't exist). The definition of locality is 'an event cannot happen at the same time as its cause if they are spatially separated'. Locality - as in space.

I'm more interested in how non-local QM can be made covariant.