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18 hours ago, joigus said:
On 11/11/2022 at 2:52 AM, bangstrom said:

What is so wrong about this statement? Essentially it says that every particle, given enough time, will eventually interact with another particle. I don't find that to be so controversial.

It is simply not true that every particle, given enough time, will eventually interact with another particle. Two photons that are being lost beyond the cosmic horizon in opposite directions, eg, will never meet again, or interact in any way.

You are reading something into it that isn't there. Each photon will eventually strike another particle. Not necessarily the other photon or any specific particle.  Just another particle.

 

18 hours ago, joigus said:

False, shockingly ignorant statement. Entanglement always occurs as a consequence of local interactions. Particles must be brought together for them to entangle. Here. Simple Google search of "what causes particle entanglement":

I don’t agree that a local interaction is required to initiate entanglement although that is necessary for experimental sources. Any non-local, two-way interaction among particles, usually electrons, such as Cramer’s advanced and retarded potentials constitutes an entanglement.

 

18 hours ago, joigus said:

You're misquoting here, or just plain lying. Point to me where anybody said that "the ambiguous nature of SR events for different observers can reverse the order of time-like (separated) events." This, most likely, is a new half-digested regurgitation from your mind of what others have actually said.

If you can have numerous observers in different inertial reference frames all claiming a different timing and different orders of the same event, I call that “ambiguous”. That may not be the best word but it appeared to be a fit regurgitation at the time and it was mine.

 

18 hours ago, joigus said:

Missing the point again. I will rephrase correctly your gazpacho of words and, with any luck, you will see what you said wrongly:

The observation of one quantum property cannot indicate the possible outcome of any other incompatible quantum property.

That sounds like a line from my gazpacho in support of Bell’s analysis. To continue:

 

18 hours ago, joigus said:

The observation of one quantum property completely determines the possible outcome of the compatible quantum property that's tied to it by a conservation law.

I say the observation of one property determines nothing about the possible outcome of any of the others, with the one exception of the same property to be observed with the other entangled particle.

I think our difference in opinion is with quantum properties having cohorts. Classical objects have cohorts but quantum particles do not so any of the combinations in your “Collectivity (2)” are possible.

No quantum properties necessarily go together. If you have a quantum coin that is heads on one side and tails on the other- and red on one side and blue on the other- you can get Heads- Red one time and Heads-Blue the next. Quantum properties do not cohort and that is the Bell test.
 

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18 hours ago, Eise said:

 If you would draw a simple space diagram, yes, then there is a space distance between particles at different locations.

I don’t know if you noticed but the first part of my statement was self contradictory because I inadvertently omitted a word. I intended to say interacting particles can not have a space-like separation.

In the second part, where I said that any two particles in different locations have a space-like separation, I was referring to different locations in the usual sense of ‘different locations’ not to locations on a diagram. So your comments about diagrams do not apply.

18 hours ago, Eise said:

Nobody here defended that there are observers that see time-like separated events in a different timely order.

I made a statement that, with entangled particles, the “first particle observed” breaks the entanglement for both particles simultaneously.

The result was that everyone, including yourself as I recall, were claiming that different observers see space-like events differently so no one could say which observation came first therefore I was ignorant of SR because I ignored SR in my explanation.

I agreed that remote observers may not know which came first but the “particles know” which was ‘first observed’ and no outside SR observations could change the order of events.

I don’t know if anyone got the message that SR was irrelevant to the problem because the bickering about my omission of SR continued for much longer than it should have.

 

18 hours ago, Eise said:

All this confusion arises because you are so sloppy with what a space-time diagram depicts, namely events, not physical objects. A physical object A in a space-time diagram is a chain of events, A being at x1 at t1, at x2 at t2, etc. Drawn all infinitesimal positions and times, the physical object A will show as a world-line, never as an individual point.

I was not aware that a space-time diagrams should plot events and not physical objects. You can't have events without physical objects so I would would think plotting one would be redundant to plotting the other.

All the light cones I have seen, do plot physical objects and they plot them as world-lines. Never as points.

 

18 hours ago, Eise said:

Again, your use of the concepts in your arguments are so vague, that they are, well, not even wrong. They miss the matter under discussion completely.

 

I was not aware that my arguments are so vague. Could you point which of my depictions of a space-time diagram got you so confused, or in the future, let me know when my arguments are vague.

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2 hours ago, bangstrom said:

I think our difference in opinion is with quantum properties having cohorts. Classical objects have cohorts but quantum particles do not so any of the combinations in your “Collectivity (2)” are possible.

That's exactly the point. Quantum systems do not have "internal cohorts." No internal cohort of elements with attributes can explain their correlations. Read it again, and you may finally understand this.

If you insist on these properties to arise from any kind of internal cohort, whatever the wave function represents --either our knowledge of the system or some "real wave" carrying our knowledge of the system-- would have to be updated non-locally. "The internal cohorts" would have to change their composition in a coordinated way, at a distance, even when separated by space-like intervals.

But none of this represents any interaction. It represents updating of your knowledge of the system. You now know more about the system than you knew before, that's all. The fact that the position variables play no role, and you can conduct the experiment at one small region of space, and the results would be exactly the same, should give it away.

 

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21 hours ago, joigus said:

That's exactly the point. Quantum systems do not have "internal cohorts." No internal cohort of elements with attributes can explain their correlations. Read it again, and you may finally understand this.

There are no cohorts among quantum properties but there is a non-local connection among entangled particles that maintains correlation.

Are you implying that entanglement itself is a cohort?

21 hours ago, joigus said:

If you insist on these properties to arise from any kind of internal cohort, whatever the wave function represents --either our knowledge of the system or some "real wave" carrying our knowledge of the system-- would have to be updated non-locally. "The internal cohorts" would have to change their composition in a coordinated way, at a distance, even when separated by space-like intervals.

Non-local updating of the system without ‘hidden variables’ is a generally accepted principle of QM. The non-local updating of the system is what Einstein objected to as, “Spooky action” but it has been routinely verified as a real effect ever since it was first demonstrated by Bell.

21 hours ago, joigus said:

But none of this represents any interaction.

Why is this not an interaction?

21 hours ago, joigus said:

It represents updating of your knowledge of the system. You now know more about the system than you knew before, that's all.

It represents an updating of the system itself. Your observation tells you that the system has been updated but the system was updated whether you are aware of it or not.

21 hours ago, joigus said:

The fact that the position variables play no role, and you can conduct the experiment at one small region of space, and the results would be exactly the same, should give it away.

Experiments involving entanglement work over both large or small distances and there are no 'hidden variables' in position.

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22 hours ago, bangstrom said:

In the second part, where I said that any two particles in different locations have a space-like separation, I was referring to different locations in the usual sense of ‘different locations’ not to locations on a diagram. So your comments about diagrams do not apply.

So that means your argument is not relevant. That particles at different locations have a space distance is a tautology. That two measurements are space-like separated in a space-time diagram is not. This is just one example of you confusing, or better, obfuscating, the discussion again and again. (Calling' non-locality' 'not realist' is another one.)

22 hours ago, bangstrom said:

I agreed that remote observers may not know which came first but the “particles know” which was ‘first observed’ and no outside SR observations could change the order of events.

As repeatedly said, the inertial frame of the entanglement source and the measurement devices is not a privileged frame. There is no 'objective now', and no absolute timely order for space-like separated events, so no objective first. There is no way, even for the measurements themselves, to 'know' if its entangled partner has been measured. There is no flipping of the wave function before it is measured: there are only measurements.

22 hours ago, bangstrom said:

I don’t know if anyone got the message that SR was irrelevant to the problem because the bickering about my omission of SR continued for much longer than it should have.

It takes so long because you do not see the relevance of it. You only show again and again that you do not understand SR, and therefore you do not understand the relevance. 

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9 hours ago, bangstrom said:

Are you implying that entanglement itself is a cohort?

This sentence doesn't make sense gramatically, let alone physically.

A cohort is a set.

I'll get back to you later.

:doh:

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On 11/13/2022 at 11:17 AM, bangstrom said:

I don’t know if anyone got the message that SR was irrelevant to the problem because the bickering about my omission of SR continued for much longer than it should have.

SR is relevant to everything physics. It's the local limit of GR, it's the basis of QFT. There are no known experimental exceptions to it. Analysis and theoretical discussion on how nothing about QM can contradict its salient facts has been the subject of study for decades.

I suggest you study thoroughly how it underpins all of physics. It will be very illuminating.

You cannot just say "oh, but this is not SR," and get away with it.

About "bickering,"

If people tell you there are non winged lions, that's not bickering. That's stating something that's very likely to be true. It's for your own intellectual good when people tell you so.

There are no winged lions, and there is no contradiction to special relativity.

You can take that to your grave. I'll take it to mine.

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20 hours ago, Eise said:

So that means your argument is not relevant. That particles at different locations have a space distance is a tautology. That two measurements are space-like separated in a space-time diagram is not. This is just one example of you confusing, or better, obfuscating, the discussion again and again. (Calling' non-locality' 'not realist' is another one.)

I was discussing two objects in ordinary space. You assumed I was discussing a diagram. I was not discussing a diagram so the confusion was on your end.

20 hours ago, Eise said:

As repeatedly said, the inertial frame of the entanglement source and the measurement devices is not a privileged frame. There is no 'objective now', and no absolute timely order for space-like separated events, so no objective first.

I never claimed the inertial frame of the experiment was a ‘privileged’ frame. As usual, it was a frame of its own.

20 hours ago, Eise said:

There is no way, even for the measurements themselves, to 'know' if its entangled partner has been measured. There is no flipping of the wave function before it is measured: there are only measurements.

I said the particles ‘know’ which was measured first. That was a teleological statement but how better to say it?

20 hours ago, Eise said:

It takes so long because you do not see the relevance of it. You only show again and again that you do not understand SR, and therefore you do not understand the relevance. 

If you understand SR, you should know that observers from outside a single reference frame can not go back in time and change events that have already happened to conform to their various outside observations.

 

5 hours ago, joigus said:

You cannot just say "oh, but this is not SR," and get away with it.

About "bickering,"

If people tell you there are non winged lions, that's not bickering. That's stating something that's very likely to be true. It's for your own intellectual good when people tell you so.

 

The "people" in this case were telling me SR applies across reference frames. I was saying that ain't so.

11 hours ago, joigus said:
21 hours ago, bangstrom said:

Are you implying that entanglement itself is a cohort?

This sentence doesn't make sense gramatically, let alone physically.

A cohort is a set.

An ‘entanglement’ is a ‘set’ of two or more particles that may be widely separated in space but they act as if they were side-by-side.

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1 hour ago, bangstrom said:

I was discussing two objects in ordinary space.

Which is not relevant at all for the point we are making with our references to SR. You could just as well have said "the earth is a sphere": it is true, but not relevant when discussing space-like separated measurements. Again: the improvement of Aspect's experiments compared to Clauser's, was that the measurements were space-like separated, i.e. even a light signal would not be fast enough to 'tell' the other measurement what it should be.

1 hour ago, bangstrom said:

I never claimed the inertial frame of the experiment was a ‘privileged’ frame.

Yes, you did:

On 11/13/2022 at 11:17 AM, bangstrom said:

I agreed that remote observers may not know which came first but the “particles know” which was ‘first observed’ and no outside SR observations could change the order of events.

Here you take the inertial frame of the entanglement source and the measurement devices as a preferred frame. There is no change in order of events. With space-like separated events there is no objective order of events. For one observer measurement 1 might be first, for another measurement 2. Nothing changes. It is only a change of perspective. 

1 hour ago, bangstrom said:

I said the particles ‘know’ which was measured first. That was a teleological statement but how better to say it?

It's OK, I didn't criticise your anthropomorphic expression. I even went with it, and I do it here again: no, there is no way that on basis of a measurement one can know if the other was already measured or not. If you think you can, then show us how. But with space-like separated events, mind you, in the SR meaning of the word, not with 'space distance'. 

1 hour ago, bangstrom said:

If you understand SR, you should know that observers from outside a single reference frame can not go back in time and change events that have already happened to conform to their various outside observations.

I nowhere said such a thing. If you think I did, cite the relevant text passage.

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2 hours ago, bangstrom said:

The "people" in this case were telling me SR applies across reference frames. I was saying that ain't so.

Yes, you're saying this since day one. I will repeat: SR always applies in sufficiently small regions of space-time. There is no known experimental exception to it, and there's no reason to expect any. Quantum entanglement is every bit as compliant with SR as every other physical process we know. If you think this not to be the case, explain why with theoretical arguments from mainstream physics, or direct us to the experimental evidence. So far you're just parrotting unsubstanciated claims by other people. We are all aware of the existence of these claims, as we are aware of the existence of bad music. There's a thin line separating serious science from free-floating fantasy, and some people take every oportunity wherever they find ambiguity, or a grey area, to cross that line. There's bad science too, you know? I wasn't born yesterday.

2 hours ago, bangstrom said:

An ‘entanglement’ is a ‘set’ of two or more particles that may be widely separated in space but they act as if they were side-by-side.

No. An Entanglement is a property that only very special many-particle states satisfy. It's not a set of entities having properties according to which we can do statistics. The statistics of such properties is hardwired in the state without them being "real" properties of the individual entities. The entangled state is the entity as far as the current theory understands it.

No quantum numbers of spin make up the Bell state. The individual quantum numbers are totally undetermined. The eigenstates are totally undetermined. The particle identities are totally undetermined. There's no cohort. There's no set of internal colours, markers, tags. So far as we know today, there isn't. Maybe in the future someone will come up with an idea to weaken the criterion of reality to define these variables and make it all consistent with known physics, but so far it hasn't happened.

Entanglement is a property in itself (the ending "-ment" should give it away). A cohort is a set of individuals with properties (like, eg, people aged between 16 and 20, unemployed, and single.) So no, you're not dealing with this topic with any degree of scientific of philosophical care. You're obviously ignorant of relativity, as well as of how and why it's critical in this discussion.

17 minutes ago, Eise said:

Here you take the inertial frame of the entanglement source and the measurement devices as a preferred frame. There is no change in order of events. With space-like separated events there is no objective order of events. For one observer measurement 1 might be first, for another measurement 2. Nothing changes. It is only a change of perspective. 

Yes. At least @MigL has told him, you @Eise have told him --and he's telling you again--, and I have told him.

17 minutes ago, Eise said:

It's OK, I didn't criticise your anthropomorphic expression. I even went with it, and I do it here again: no, there is no way that on basis of a measurement one can know if the other was already measured or not. If you think you can, then show us how. But with space-like separated events, mind you, in the SR meaning of the word, not with 'space distance'. 

I had no objection to that anthropomorphic expression either. I think everyone involved in this thread understood it is just a manner of speaking.

Edited by joigus
minor addition + person-addressing change
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On 11/11/2022 at 6:25 PM, joigus said:

a married person

Maybe not intended but I see this as yet an analogy for entanglement. Assume a couple is married and then separated by some (great) distance. When one (random) individual of the married couple dies we immediately know that the other party has become a widower or a widow. The immediate change from wife to widow (or husband to widower) does not need a signal.

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2 hours ago, Ghideon said:

Maybe not intended but I see this as yet an analogy for entanglement. Assume a couple is married and then separated by some (great) distance. When one (random) individual of the married couple dies we immediately know that the other party has become a widower or a widow. The immediate change from wife to widow (or husband to widower) does not need a signal.

Man oh, man. That's a great analogy!!! +1

It's freakin' brilliant.

You've made the other person a widow or widower, without actually doing anything to them. You have learnt something about them because of what you've done at one point. You know something about the other person's future. But the other person, and those around her or him, are clueless until the "classical data" are sent to them. Those classical data are under the constraints of delay, because they do have to use a signal.

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23 hours ago, Eise said:
On 11/14/2022 at 11:40 PM, bangstrom said:

I never claimed the inertial frame of the experiment was a ‘privileged’ frame.

Yes, you did:

23 hours ago, Eise said:

I never claimed the inertial frame of the experiment was a ‘privileged’ frame.

Sorry, the first part or this was omitted so I will repeat it in the next comment.

My underline.

In physics, the term ‘preferred frame’ or ‘privileged frame’ has a specific meaning much different from the common usage of the word meaning favored or selected. It has a cosmological meaning unrelated to anything we were discussing. So I never claimed my frame was ‘privileged’.

Using a local reference frame to the exclusion of others is a normal and accepted practice. It is absolutely not the same as a ‘preferred frame’.

A ‘preferred frame’ is a global reference frame that unifies all reference frames. Various preferred frames, such as the CMBR, have been proposed but so far they have all been proved unworkable so there is really no such thing as a preferred frame.

This is from Wikipedia,

"In theoretical physics, a preferred frame or privileged frame is usually a special hypothetical frame of reference in which the laws of physics might appear to be identifiably different (simpler) from those in other frames.

In theories that apply the principle of relativity to inertial motion, physics is the same in all inertial frames, and is even the same in all frames under the principle of general relativity."

 

23 hours ago, Eise said:

there is no way that on basis of a measurement one can know if the other was already measured or not. If you think you can, then show us how.

If it is necessary to know which measurement came first, the experimenters can decide which measurement to make first. Easy-peasy.

Usually it is not necessary to know which came first and the measurements may not be able to determine which was first but that only means that the timing was below the device's threshold of measurement.

On the other hand, when one particle is measured, the other responds correctly by being predictably anti-coordinated so the second measured particle apparently ‘got the message’ no matter how quickly or beyond measure the timing was.

23 hours ago, Eise said:
On 11/14/2022 at 11:40 PM, bangstrom said:

If you understand SR, you should know that observers from outside a single reference frame can not go back in time and change events that have already happened to conform to their various outside observations.

I nowhere said such a thing. If you think I did, cite the relevant text passage.

That was one of MY explanations for why SR considerations are neither relevant nor used in the the calculations. I made no claim that you said that. You would have been right if you did.

 

23 hours ago, Eise said:

Here you take the inertial frame of the entanglement source and the measurement devices as a preferred frame. There is no change in order of events. With space-like separated events there is no objective order of events. For one observer measurement 1 might be first, for another measurement 2. Nothing changes. It is only a change of perspective. 

My underline.

In physics, the term ‘preferred frame’ or ‘privileged frame’ has a specific meaning much different from the common usage of the word meaning favored or selected. It has a cosmological meaning unrelated to anything we were discussing. So I never claimed my frame was ‘privileged’.

Using a local reference frame to the exclusion of others is a normal and accepted practice. It is absolutely not the same as a ‘preferred frame’.

A ‘preferred frame’ is a global reference frame that unifies all reference frames. Various preferred frames, such as the CMBR, have been proposed but so far they have all been proved unworkable so there is really no such thing as a preferred frame.

This is from Wikipedia,

"In theoretical physics, a preferred frame or privileged frame is usually a special hypothetical frame of reference in which the laws of physics might appear to be identifiably different (simpler) from those in other frames.

In theories that apply the principle of relativity to inertial motion, physics is the same in all inertial frames, and is even the same in all frames under the principle of general relativity."

18 minutes ago, bangstrom said:

 

 

23 hours ago, joigus said:

The statistics of such properties is hardwired in the state without them being "real" properties of the individual entities. The entangled state is the entity as far as the current theory understands it.

It is more like they are soft-wired since we know nothing about the properties of entangled particles until observed and then it all comes together.

11 hours ago, Ghideon said:

The immediate change from wife to widow (or husband to widower) does not need a signal.

In the actual experiment, the first particle observed instantly makes the other particle the second particle to be observed. You should write a paper.

Edited by bangstrom
Tried to add a missing quote but it didn't work
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3 hours ago, bangstrom said:

In physics, the term ‘preferred frame’ or ‘privileged frame’ has a specific meaning much different from the common usage of the word meaning favored or selected. It has a cosmological meaning unrelated to anything we were discussing. So I never claimed my frame was ‘privileged’.

Cosmology is of no relevance here. Experimenters doing quantum interferometry, quantum teleportation, and the like, do not refer anything to the CMB. That would be silly.

The CMBR is distinguished from a cosmological POV, not from a POV of local quantum mechanics.

3 hours ago, bangstrom said:

If it is necessary to know which measurement came first, the experimenters can decide which measurement to make first. Easy-peasy.

Seems trivial to you only because you do not understand, and looks now as if you will never do. The experimenters decide who does the measurement: One of them, the other, or both. And they also decide when that happens, in their respective local reference frame. OTOH, observers moving with respect to them, see the measurements happen in different temporal order, depending on their state of motion. Will you at some point understand this?

3 hours ago, bangstrom said:

It is more like they are soft-wired since we know nothing about the properties of entangled particles until observed and then it all comes together.

You have a flair for getting everything backwards like I've never seen before. Everything is together --non-separable, that's why I say it's "hardwired," and it comes apart after we do the measurement --the particles become disentangled, and the density matrix goes from pure state to strict mixture state.

3 hours ago, bangstrom said:

In the actual experiment, the first particle observed instantly makes the other particle the second particle to be observed. You should write a paper.

Nothing is observed until it is observed. There is no signal. Filtering measurements carry no signal either. In this way, it's similar to a non-interaction measurement, like counterfactuals --Elitzer-Vaidman bomb tester-- or filterings.

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6 hours ago, bangstrom said:

In physics, the term ‘preferred frame’ or ‘privileged frame’ has a specific meaning much different from the common usage of the word meaning favored or selected. It has a cosmological meaning unrelated to anything we were discussing. So I never claimed my frame was ‘privileged’.

It is obvious what I mean: again you are obfuscating the discussion. Of course I mean it in the context of SR: all inertial reference frames are equally valid; none is privileged, not even the inertial frame where entanglement source and measuring devices are at rest. So if we have two events, e.g. two measurements, that are space-like separated, there is no fixed timely order. 

6 hours ago, bangstrom said:

If it is necessary to know which measurement came first, the experimenters can decide which measurement to make first. Easy-peasy.

You are moving the goal posts. Yes, it is easy, just setup the experiment so that the measurements are time-like separated. But that was not what we are talking about. You are evading the point we are making.

6 hours ago, bangstrom said:

On the other hand, when one particle is measured, the other responds correctly by being predictably anti-coordinated so the second measured particle apparently ‘got the message’ no matter how quickly or beyond measure the timing was.

As you know, we say there is no message. And one of the ways of seeing that is that when the two measurements are space-like separated, the timely order is different for different observers. Signals have a direction. But a signal going into one direction for one observer, but in another direction for another observer makes no sense physically.

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Just now, iNow said:

19 pages in and you're just now picking up on this? ;)

No, I noticed earlier, but I always give people the benefit of the doubt. Maybe bangstrom has some problems understanding texts, maybe he doesn't know SR, etc... But I already called him a troll much earlier: 

On 10/20/2022 at 11:51 AM, Eise said:

Troll.

Page 14 :rolleyes:

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I have to agree with INow; this is just going around in circles.

It is an established fact, that Quantum Mechanics does not display any indication of a 'reality' before a measurement is made.
( Sometimes even after. Is it a particle or a wave ? Depends on the measurement made )
This is true for solitary particles, let alone entangled pairs.
It is not a matter of states switching back and forth between possibilities; there are no actual states defined.
But while the states themselves are not realized, the correlation between them is, and is defined by the common wave function.
A correlation does not have to be 'maintained' in any way, it simply is, or isn't; no 'signalling' required.
All this points to 'non-relity' being the root cause of the behaviour of entangled pairs, certainly not 'non-locality', as there is no need for it after 'non-reality' is taken into consideration.

And I have to agree; Bangstrom should stop trying to understand entanglement until he has a better understanding of SR.

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10 hours ago, bangstrom said:

In the actual experiment, the first particle observed instantly makes the other particle the second particle to be observed.

That seems incompatible with Special Relativity.

Clarification: I'm sure the actual experiment is consistent with Special Relativity, your explanation is not.

Edited by Ghideon
Clarification
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4 hours ago, iNow said:

19 pages in and you're just now picking up on this? ;)

 

2 hours ago, MigL said:

I have to agree with INow; this is just going around in circles.

You guys are forgetting that sometimes we are surprised with a gem by other members. I personally find @Ghideon's analogy of the widow/widower very illuminating. I've been trying for years to find an analogy that illustrates this particularly difficult point that you can instantly obtain information about a remote thing without physically affecting it, and there you are --and the example not being quantum mechanical. To me, it's worth all the effort spent.

Here it is again:

22 hours ago, Ghideon said:

Assume a couple is married and then separated by some (great) distance. When one (random) individual of the married couple dies we immediately know that the other party has become a widower or a widow. The immediate change from wife to widow (or husband to widower) does not need a signal.

 

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19 hours ago, joigus said:

The experimenters decide who does the measurement: One of them, the other, or both. And they also decide when that happens, in their respective local reference frame.

That's what I said. If it matters to know which measurement came first, the experimenters can decide which to measure first.

 

19 hours ago, joigus said:

OTOH, observers moving with respect to them, see the measurements happen in different temporal order, depending on their state of motion. Will you at some point understand this?

I have explained many, many times I understand this. What are you saying I don't understand?

 

16 hours ago, Eise said:

It is obvious what I mean: again you are obfuscating the discussion. Of course I mean it in the context of SR: all inertial reference frames are equally valid; none is privileged, not even the inertial frame where entanglement source and measuring devices are at rest. So if we have two events, e.g. two measurements, that are space-like separated, there is no fixed timely order. 

Agreed, a purely space-like separation has no timely order.

Also, the term 'privileged reference frame' is specifically a cosmological term and one that I would not use in reference to an ordinary reference frame so your claim that I did had me confused.

16 hours ago, Eise said:

You are moving the goal posts. Yes, it is easy, just setup the experiment so that the measurements are time-like separated. But that was not what we are talking about. You are evading the point we are making.

I understand the point you were making but, in reality, when two different measurements are made in the 'real' world it has to be nearly impossible to make both measurements at absolutely and precisely the same femtosecond or less so there will always be a first measured.

 

17 hours ago, Eise said:

As you know, we say there is no message.

 I know you say there is no message. But I say there does appear to be evidence of a signal and response and that is suggestive of a message being sent and received so I am not convinced.

 

17 hours ago, Eise said:

And one of the ways of seeing that is that when the two measurements are space-like separated, the timely order is different for different observers. Signals have a direction. But a signal going into one direction for one observer, but in another direction for another observer makes no sense physically.

Different observers seeing signals going in different directions is a well understood phenomenon of SR. It may be counter intuitive but I don't understand how it means there is no signal.

It also makes no difference to the measurements at the local level of the experiment itself.

.

14 hours ago, Ghideon said:
On 11/16/2022 at 12:59 AM, bangstrom said:

In the actual experiment, the first particle observed instantly makes the other particle the second particle to be observed.

That seems incompatible with Special Relativity.

Clarification: I'm sure the actual experiment is consistent with Special Relativity, your explanation is not.

Agreed, changing the names to first observed and second observed or to widow and widower has nothing to do with SR.

Also, the experiments with entanglement are consistent with SR because they are designed with SR in mind.

They are perfectly symmetrical with pairs of entangled particles originating in the precise center between two measuring devices so the measurements on both ends are made simultaneously. This eliminates any time variations due to either classical or relativistic variations.

16 hours ago, MigL said:

I have to agree with INow; this is just going around in circles.

Very much so- right from the start.

 

16 hours ago, MigL said:

But while the states themselves are not realized, the correlation between them is, and is defined by the common wave function.

A correlation does not have to be 'maintained' in any way, it simply is, or isn't; no 'signalling' required. All this points to 'non-relity' being the root cause of the behaviour of entangled pairs, certainly not 'non-locality', as there is no need for it after 'non-reality' is taken into consideration.

Could it be that the common wave function that “defines” the correlation is a form of ‘signal’ that maintains correlation?

I don’t find the view that a correlation is because “it simply is” as explanatory when the quantum identities are indeterminate until observed and entangled particles always appear anti-coordinated even when separated by a great distance.

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1 hour ago, bangstrom said:

I understand the point you were making but, in reality, when two different measurements are made in the 'real' world it has to be nearly impossible to make both measurements at absolutely and precisely the same femtosecond or less so there will always be a first measured.

The measurements do not have to be 'at the same femto second' in the rest frame of the experiment. To be space-like separated is enough. As in Aspect's 'real world' experiment.

1 hour ago, bangstrom said:

Different observers seeing signals going in different directions is a well understood phenomenon of SR.

Really? A real signal, i.e. transferring information (and therefore at least a minimum amount of energy)? Or will you beg the question, and will give entanglement as example? So, please, give an example of such a signal, but not concerning entanglement.

1 hour ago, bangstrom said:

They are perfectly symmetrical with pairs of entangled particles originating in the precise center between two measuring devices so the measurements on both ends are made simultaneously.

Simultaneous according which observer? Simultaneity is not even agreed upon by different observers for time-like separated events. Only the timely order is.

Edited by Eise
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2 hours ago, Eise said:

Really? A real signal, i.e. transferring information (and therefore at least a minimum amount of energy)? Or will you beg the question, and will give entanglement as example? So, please, give an example of such a signal, but not concerning entanglement.

Information has no energy and a signal need not be energy bearing. The question is, if an electron on one end of an entanglement is found to be spin-up, how does it's former partner in the entanglement instantly 'know' it should be spin-down?

 

2 hours ago, Eise said:

Simultaneous according which observer? Simultaneity is not even agreed upon by different observers for time-like separated events. Only the timely order is.

Simultaneous within the reference frame of the experiment itself and its measurements. Or, simultaneous relative to the origin of the entangled particles if you want to be really precise.

The detectors are ideally widely spaced so the events will never be simultaneous to all observers but that has no relevance to the experiment or its measurements since outside observations can not change the results.

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3 hours ago, bangstrom said:

Agreed, changing the names to first observed and second observed or to widow and widower has nothing to do with SR.

In SR and in my analogy, there is no global first or second observation. I did think about SR but did not want to complicate my analogy by introducing comments on SR; there may be participands in the thread that may miss the point due to limited knowledge about relativity.

 

It could be interesting to probe the limits of the analogy and where it breaks down due to relativity and properties of QM if anyone is interested, but that may be a separate thread. 

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