EPR & SR

[Genady]

5 minutes ago, sethoflagos said:

I don't have quite enough hubris to imagine that I can advance physics, but I would like to have at least a consistent picture in my head of what might be going on. Isn't there an 'advanced wave' available in the wave equation that might assist with the time reversed signalling?

I don't think it can be done generally. The QM calculation for the states of spin-entangled electrons, for example, is just a vector algebra (in the 2D complex vector space). There is no time in this calculation at all. Nor space. However, it describes the entire phenomenon.

[sethoflagos]

2 minutes ago, Genady said:

I don't think it can be done generally. The QM calculation for the states of spin-entangled electrons, for example, is just a vector algebra (in the 2D complex vector space). There is no time in this calculation at all. Nor space. However, it describes the entire phenomenon.

Surely this is no more than a temporary common property of the pair? An entire description would include a mapping of their kinetic timeline for example, wouldn't it?

[Markus Hanke]

1 hour ago, sethoflagos said:

Parsimony would suggest to me some mechanism whereby a 'request for clarification' is sent (yes, ok, backwards in time) to the source

This is pretty much what happens in what is called the “transactional interpretation” of QM. Needless to say that, just as the case with all interpretations, there are problems and issues with this, but truth be told I’m not familiar enough with this particular interpretation to offer more meaningful details.

4 hours ago, Lorentz Jr said:

Just the combination of "purely statistical" and "phenomenon". Semantically speaking, I think it goes a little too far towards suggesting a lack of causation.

I think we have somewhat different ideas about what it actually is that physics as a discipline does. To me, physics makes descriptive models of certain aspects of the world around us; it is not in the business of putting forth ontological claims about “what things really are”. That job description belongs more to philosophy, though clearly there is a large amount of overlap too.

Thus, to me, the standard QM formalism for entanglement is a pretty thorough description of what goes on here. I see no a priori reason why any other kind of causal mechanism must necessarily be involved in this. The initial interaction, to me, provides enough of a causal mechanism.

You’re probably familiar with the old classical analogy of a pair of gloves being put into separate boxes (so that the handlers don’t know which glove is in which box), and those boxes then mailed to distant locations. Upon opening, and subsequent comparison of their handedness, a perfect anti-correlation will always be found. What is the causative mechanism of that anti-correlation? It’s because the statistical correlation was set up this way from the beginning, when the pair of gloves was first distributed into the boxes - there is no additional mechanism or interaction that is triggered by opening the boxes, somehow acting non-locally. We simply set up a correlation, which is then maintained through time. Thus, the statistical (anti-)correlation is a complete description of what goes on here; no further causative mechanisms are required, and you would probably agree with me that there is no mystery at all involved in any aspect of the glove scenario. You get either |LR> or |RL>, but never |LL> or |RR>.

Quantum entanglement is really not much different - the only difference is that, unlike in the classical case involving gloves, there is no local realism, so there is no meaningful way to speak of the “state” of the system, unless a measurement is performed. That makes it all seem much more mysterious than it actually is; but ultimately the principle is the same one - a correlation is prepared by letting the particles interact in a certain way, and this correlation then persists up until an observation takes place. Note also that the act of measurement is itself a form of entanglement - when you measure one particle, it ceases to be entangled with the other particle, and instead becomes entangled with the measurement apparatus. How’s that for a head-wrecker  

[Genady]

2 hours ago, sethoflagos said:

It's this second global transformation that is problematic.

There is a completely different possibility avoiding this apparent problem without going backwards in time or faster than light: nothing is in fact random. Not only the results of the measurements, but also the measurements themselves. All is completely determined, not just since the particles were prepared in the entangled state, but way before that, since these particles, or their ancestor particles, and the particles of Alice and Bob, and particles of the rest of the universe were "on top of each other" and interacted among themselves. It is pre-determined when and how the particles will be entangled and everything that happens to them, and to Alice and Bob, after that (I've learned this idea from 't Hooft.)

[Lorentz Jr]

37 minutes ago, Markus Hanke said:

I think we have somewhat different ideas about what it actually is that physics as a discipline does. To me, physics makes descriptive models of certain aspects of the world around us; it is not in the business of putting forth ontological claims about “what things really are”.

Yes, and you're in the majority these days, so I should probably learn to keep my mouth shut about this subject. It's just that your phrasing seems to me to deny the existence of any ontology at all. Anyway, I think we've both made our points. Thanks for chatting. 🙂

[sethoflagos]

48 minutes ago, Markus Hanke said:

This is pretty much what happens in what is called the “transactional interpretation” of QM. Needless to say that, just as the case with all interpretations, there are problems and issues with this, but truth be told I’m not familiar enough with this particular interpretation to offer more meaningful details.

Thanks Markus. So at some point, my line of reasoning has become simply a personal preference over other quite valid viewpoints. I'm okay with that.

12 minutes ago, Genady said:

There is a completely different possibility avoiding this apparent problem without going backwards in time or faster than light: nothing is in fact random. Not only the results of the measurements, but also the measurements themselves. All is completely determined, not just since the particles were prepared in the entangled state, but way before that, since these particles, or their ancestor particles, and the particles of Alice and Bob, and particles of the rest of the universe were "on top of each other" and interacted among themselves. It is pre-determined when and how the particles will be entangled and everything that happens to them, and to Alice and Bob, after that (I've learned this idea from 't Hooft.)

I watched a Youtube video recently on superdeterminism by Sabine Hossenfelder. She's clearly very expert in her field, and I'm sure that this interpretation fits the data too. I just don't like it as much. 

Many, many years ago I had a vision of an ancient transistor radio (see how long ago it was), floating in the vast emptiness of deep space long after humanity had been and gone. With its final flicker of power it sent a 'request for clarification' back to the dawn of time, which responded in the only way it could - by creating a universe that one day in the far, far future would see an ancient transistor radio floating in the vast emptiness of deep space.

I've lived with that picture for a very long time and whether it's true or false I've grown comfortable with it. 

[MigL]

47 minutes ago, Genady said:

All is completely determined, not just since the particles were prepared in the entangled state, but way before that, since these particles, or their ancestor particles, and the particles of Alice and Bob, and particles of the rest of the universe were "on top of each other" and interacted among themselves.

Mr W Heisenberg has some thoughts on that, and his principle says "no".

[Genady]

16 minutes ago, MigL said:

Mr W Heisenberg has some thoughts on that, and his principle says "no".

Well, t' Hooft explained how they do not contradict each other.

[Mordred]

1 hour ago, Genady said:

Well, t' Hooft explained how they do not contradict each other.

If I recall he applied this to his cellular autonoma model but its been a while since I studied cellular autonoma

[Genady]

15 minutes ago, Mordred said:

If I recall he applied this to his cellular autonoma model but its been a while since I studied cellular autonoma

Yes: 

Amazon.com: The Cellular Automaton Interpretation of Quantum Mechanics (Fundamental Theories of Physics, 185): 9783319412849: 't Hooft, Gerard: Books

[Mordred]

49 minutes ago, Genady said:

Yes: 

Amazon.com: The Cellular Automaton Interpretation of Quantum Mechanics (Fundamental Theories of Physics, 185): 9783319412849: 't Hooft, Gerard: Books

Thanks there are aspects I like in that model however I will still tend to use QFT over that lol mainly as I'm more familiar with QFT. What appeals to me in the cellular autonoma is that it helps ease numerous calculations to reasonable approximation.

This is more an FYI than in regards to the opening post. However as were onto interpretations vs correlation functions. Some of the interpretations I will actually follow without conclusion as to which is the best interpretation are those that apply mathematics with the subsequent tests of those mathematics. 

This falls into the Bell inequalities as well as CHSH inequalities how CHSH works is in itself a lengthy topic but the essence of it is that it further tests the probability vs the determinable aspects of the various correlation functions via the density matrix that is often employed... without going into the mathematics itself one should be aware that this methodology has some ramifications into the terms locality and non locality.  We tend to think this is applying the relativity definition  however this isn't necessarily true in the inequality case.

The inequality essentially separates the classical probability (local) part vs the quantum interference term (non local). 

So what are they truly saying here ? Well as I've come to understand it the local in essence means that all the variables to describe a particles evolution is local to the particle state itself. However in the quantum case for example the quantum harmonic oscillator interferes as the quantum harmonic oscillator is part of the field outside the boundary of the well defined particle then then it is non local to the potential boundary we define as the localized excitation.

this further ties into the :hidden variable aspects: Is all the information to describe the evolution history of the particle state inclusive in that particle state. (local to the particle state) though hidden. Or non local do we need to further include the field interactions (key note though those field interactions must still follow causality and speed of information exchange. I point this out as it is another commonly used descriptive of local vs non local commonly used in Bells type experiments.

a simplified version of the mathematics is as follows.

\[P_{all} (+a,+b)=Tr[M_{a}^{+ }\otimes M_{b}^{+ }](\rho_{c}+\rho_{q})\]

\[ =(+a,+b)=P_c(+a,+b)+P_q(+a,+b)\]

where M is the probability density matrix where the average values of a and b in the classical vs quantum mechanical part is

\[\langle ab\rangle=P_c(+a,+b)-P_c(a-,-b)-P_c(a+b)+P_c(-a,-b)=\cos\theta_a\cos\theta_b\]

\[\langle ab\rangle=P_q(+a,+b)-P_q(a-,-b)-P_q(a+b)+P_q(-a,-b)=\sin\theta_a \sin\theta_b] sin 2\xi\cos(\phi_a+\phi_b=2\eta)\]

 

 

 

Edited December 30, 2022 by Mordred

[sethoflagos]

6 hours ago, Mordred said:

This is more an FYI than in regards to the opening post.

I'm finding it a bit difficult to extract that information.

At least, I can't correlate your symbology with that presented on https://en.wikipedia.org/wiki/CHSH_inequality.

When I posed the OP I was quite happy to proceed on a 'no hidden variables' assumption (local or non-local), and was actually focussed on the variation of 'now'  across some region to observers in different inertial reference frames. The spread of those 'nows' resulting in some observers seeing Alice 'pull the trigger' and others, Bob in the EPR experiment. (@Markus Hanke says it was Charlie who dunnit.)

The QM implications were really for later after the SR stuff had been sorted out.    

[Mordred]

One of the things about mathematics is the symbology often takes a second place to  the relations ( I could literlly hand someone 10 different articles covering precisely the same thing and no two papers apply the same symbology) outside of common standardized forms)   However P is simply the entangled particle state with the A and B identifying each particle state whether is spin up, down, left, right, etc. M is simply the probability density matrix of each. with rho \[\rho\] being the density of the operator from that matrix. ie the momentum, position operator. the trace of matrix M can best be covered here

https://en.wikipedia.org/wiki/Trace_(linear_algebra)

however the above was simply an FYI in so far as one has to take care on how the term local vs non local applies for a given examination the usage can often vary

Edited December 31, 2022 by Mordred

[sethoflagos]

33 minutes ago, Mordred said:

One of the things about mathematics is the symbology often takes a second place to  the relations ( I could literlly hand someone 10 different articles covering precisely the same thing and no two papers apply the same symbology) outside of common standardized forms)   However P is simply the entangled particle state with the A and B identifying each particle state whether is spin up, down, left, right, etc. M is simply the probability density matrix of each. with rho

ρ

being the density of the operator from that matrix. ie the momentum, position operator. the trace of matrix M can best be covered here

 

https://en.wikipedia.org/wiki/Trace_(linear_algebra)

however the above was simply an FYI in so far as one has to take care on how the term local vs non local applies for a given examination the usage can often vary

All is clear. Thanks!

[Mordred]

your welcome

[sethoflagos]

Coincidently, a new video in the 'Closer to Truth' series that is highly relevant to many issues discussed above showed up on Youtube today.

 

Key notes: Causality; Dynamic non-locality; Future impacts Present.  

Edited December 31, 2022 by sethoflagos

[Markus Hanke]

15 hours ago, Lorentz Jr said:

It's just that your phrasing seems to me to deny the existence of any ontology at all

Well, I profess myself agnostic so far as ontology is concerned. Just think about this for a minute - in physics we are trying to make models of “the world”. But what is this world we are referring to? It is what our brains present to us as “reality”, but this reality is itself already a model; it’s a construct built up from sense impressions, as well as specific modes of representing, structuring and integrating information, such as for example concepts of “space” and “time”. It stands to reason that, if our brains and minds were substantially different, then so would be our reality, and thus the models we make of it. It is not easy to tell just which elements of reality would differ, and which ones would remain the same. 

I am not saying that there’s nothing “out there”, I just think it might not actually be so easy to disentangle what belongs to the external world, and what really belongs to our own reality-model of it, which is a construct generated by our brain.

Therefore, so far as physics is concerned, I am very careful to distinguish the map from the territory. They are not the same things at all. A map is “true” only insofar as it accurately reflects those features of the terrain which it was intended to reflect - and each and every map has limitations and things that it cannot reflect. So usefulness is a much better criterion than ontological truth, when it comes to models and theories in physics. 

16 hours ago, Lorentz Jr said:

Anyway, I think we've both made our points. Thanks for chatting. 🙂

My pleasure  

[sethoflagos]

To put some meat on the bones of the video I posted, most of the material Tollaksen refers to can be found in a paper 'New Insights on Emergence from the Perspective of Weak Values and Dynamical Non-locality', Journal of Physics: Conference Series 504 (2014)

It's available for download at  https://www.fetzer-franklin-fund.org/media/emqm13-time-symmetric-formulation-quantum-mechanics-weak-values-classical-limit-quantum-mechanics-2/

... or via my attached copy (hope this not against the rules)

Much of it is a little opaque for my level of comprehension, but I did find a few aha! moments.

 

1742-6596_504_1_0120292.pdf

[Mordred]

I'll have to study the article in greater detail however if you recall above I described how non locality vs local  defined in regards to Bell type experiments. You happened to find an article that clearly states that post.

"2.5. Dynamical nonlocality and the whole-part dialogue Dynamical nonlocality [37] impacts the dialogue concerning the relationship between parts and wholes. Motivated by the AB non-locality and by weak measurements, we look for new manifestations of the dynamics of QM which are not predicted by the dynamics of classical mechanics. The key difference is that the equation of motion of QM exhibits a new kind of non-locality, which is best described by using modular variables."

equations are 2.32 and 2.33 for this examination for the local (classical) vs non local (quantum).

 As I have time tomorrow will read it in more detail thanks for sharing

Edited December 31, 2022 by Mordred

[Lorentz Jr]

7 hours ago, sethoflagos said:

Key notes: Causality; Dynamic non-locality; Future impacts Present.

In what phenomena is the future necessarily "relevant to the present", i.e. nonlocality isn't sufficient to explain the weirdness?

Edited December 31, 2022 by Lorentz Jr

[joigus]

On 12/30/2022 at 6:52 AM, Lorentz Jr said:

Math isn't a replacement for physics. Wave functions only describe physical systems, they don't explain why outcomes are correlated. Physics is not a purely a statistical phenomenon. Correlations may be caused by FTL communication, or they may be caused by what @joigus has called "beables" that were established when the particle was created, or they may be caused by something else. But they're caused by something. They don't happen by magic. Saying correlations in physical systems have no causal explanations is like saying human beings exist with no conscious thoughts.

The term "beables" is not mine. It's due to John Bell.

The question about beables wasn't meant to address quantum correlations. Quantum correlations are sufficiently explained by wave functions once we accept Born's rule. John Bell conjectured this notion of beables in order to give total mathematical consistency to quantum mechanics, and thus escape the insatisfaction associated to the standard projection postulate. But of course no concrete formulation of beables will ever be able to circunvent the fact that quantum mechanics establishes very clear limits to what is given to us to know about "physical reality" (what we see and measure.) In that sense, and as far as I understand them, those would-be beables should not be observables. The mapping to what we perceive as reality should be expressed in such a way that their mathematical formulation made clear what is "lost in translation" so to speak, so that we perceive this projected or apparent reality that cannot be determined, even though these objects are perfectly defined at this internal, and fundamentally unobservable, level.

[sethoflagos]

2 hours ago, Lorentz Jr said:

In what phenomena is the future necessarily "relevant to the present", i.e. nonlocality isn't sufficient to explain the weirdness?

Based on my limited knowledge, I see no 'explanations' in quantum mechanics. Only (startlingly accurate) predictions of certain experimental observations.

I think the only 'necessity' as far as the various interpretations are concerned is in being able to match those predictions..

[Lorentz Jr]

11 minutes ago, sethoflagos said:

I see no 'explanations' in quantum mechanics.

Substitute "explain" with "describe" if you like that word better.

[sethoflagos]

12 minutes ago, Lorentz Jr said:

Substitute "explain" with "describe" if you like that word better.

What I'd like better is not having this thread derailed quite so much by off-topic soapboxing.

[Lorentz Jr]

1 hour ago, sethoflagos said:

What I'd like better is not having this thread derailed quite so much by off-topic soapboxing.

I was asking about the video. Given that time travel is one of the most unscientific concepts imaginable, at least from a classical point of view, I'm wondering what the justification is for invoking it. Not saying it's impossible in quantum mechanics, just wondering why it's in the video.