Exploring the EPR Paradox: Reconciling QM and SR

[rjbeery]

Before someone asks, I must add that Determinism surfaces from my interpretation because I believe that both wavelike and particle pathing choices are made via the Principle of Least Action.

 

[rjbeery]

Ahh! Dmitry you type too fast. Since this interpretation is unique (AFAIK) I'm not sure what wikipedia would have to say about it. I do welcome criticisms from the fine minds on this forum, though.

 

[DrChinese]

... Local and Deterministic Universe...

Yea, I'd have to question the deterministic part as well. I think the big item in this is the mechanism for effecting the apparently non-local phenomena we all know and love - without being non-local. :)

 

[rjbeery]

DrChinese: The Local mechanism which displays non-locality is already encapsulated in the interpretation. The apparent non-local effects occurring at A and B particles' measurement events is an illusion because both particles possessed a distinct spin at event E (where A and B Locally interacted) and proceeded to carry this spin with them to their respective measuring events. Remember it is the type of measurement taken at these measuring events that restricts the formulation of the advanced waves to ones producing a pair of particles at event E which concur with our QM findings.

 

[DrChinese]

DrChinese: The Local mechanism which displays non-locality is already encapsulated in the interpretation. The apparent non-local effects occurring at A and B particles' measurement events is an illusion because both particles possessed a distinct spin at event E (where A and B Locally interacted) and proceeded to carry this spin with them to their respective measuring events. Remember it is the type of measurement taken at these measuring events that restricts the formulation of the advanced waves to ones producing a pair of particles at event E which concur with our QM findings.

Yes, I am good with this part. I just don't think that makes it a deterministic interpretation. Deterministic (to me anyway) implies that something "caused" Alice and Bob to have the specific orientation at E. I do not think this interpretation implies that.

 

[rjbeery]

Determinism is the philosophical proposition that every event, including human cognition and behavior, decision and action, is causally determined by an unbroken chain of prior occurrences.

Literally using this definition, this interpretation is not Deterministic. Note that the above description of Determinism presumes that influences from the future cannot occur at all; it is merely dealing with the idea that everything happening now either is or is not a result of past events. And the answer to this question is deemed to be the sole arbiter of whether or not future history is set in stone. I say this is false, and that a future history can be set in stone even if some phenomena are retro-causal. When I say Deterministic I mean that there is a single history, from beginning to end, with no random, uncertain or acausal events. If all effects are the result of causes, and if Physics follows the Principle of Least Action for both particle and wavelike influences, then I believe this interpretation is Deterministic*. We could take Cramer's cue and call it Weak Determinism by removing the temporal restriction, if you wish...

* Deterministic under the mildly revised definition of being "the philosophical proposition that every event, including human cognition and behavior, decision and action, is causally determined".

 

[DrChinese]

Literally using this definition, this interpretation is not Deterministic. Note that the above description of Determinism presumes that influences from the future cannot occur at all; it is merely dealing with the idea that everything happening now either is or is not a result of past events. And the answer to this question is deemed to be the sole arbiter of whether or not future history is set in stone. I say this is false, and that a future history can be set in stone even if some phenomena are retro-causal. When I say Deterministic I mean that there is a single history, from beginning to end, with no random, uncertain or acausal events. If all effects are the result of causes, and if Physics follows the Principle of Least Action for both particle and wavelike influences, then I believe this interpretation is Deterministic*. We could take Cramer's cue and call it Weak Determinism by removing the temporal restriction, if you wish...

* Deterministic under the mildly revised definition of being "the philosophical proposition that every event, including human cognition and behavior, decision and action, is causally determined".

I see this point, however, I really don't think this restores any kind of determinism. We still don't have any explanation of WHY correlated photons Alice and Bob have spin up vs. spin down, etc. There is no apparent possibility of answering this either. (Now please keep in mind that I don't in any way consider that a weakness or a criticism.) Instead, you end up postulating some kind of stochastic mechanism which is still outside of the interpretation... just as you might in any interpretation. And that doesn't really make it deterministic.

In other words: with this interpretation, we can answer the question ["how do apparently non-local correlations arise"] but we cannot answer the question ["where are the hidden variables"] ? We would say that SOME of the hidden variables where found to reside in the future. But clearly some variables are missing (since the actual observed values are not explained anywhere), and there is clear contextuality as well (I question whether any contextual interpretation can also be deterministic, although I am not certain about that).

 

[Dmitry67]

wait, wait, "weak causality" is a good point, but even without it TI is explicitly non-deterministic. Just on a first found link:

http://www.npl.washington.edu/npl/int_rep/tiqm/TI_38.html#3.8

The TI also clarifies, but does not solve, the problem of predictivity. As was discussed in Section 3.2, the beginning of a transaction can be viewed as the emitter sending out a retarded "offer" wave in various directions and receiving an "echo" back from the absorber in the form of an advanced confirmation wave which has an amplitude proportional to * (where is the complex OW evaluated at the absorber locus). In the usual circumstance there are a very large number of potential future absorbers, and if all provide such echoes, the emitter, at the instant of emission, has a large menu of possible transaction possibilities from which to choose. In a single quantum event the boundary conditions will permit only one event to occur.

Born's probability law is therefore a statement that the probability of occurrence of a given transaction is proportional to the magnitude of the echo corresponding to that transaction which the emitter receives.

 

[rjbeery]

but we cannot answer the question ["where are the hidden variables"] ?

I'm not sure about that (meaning, I'm not sure one way or the other). As you mentioned, this interpretation already provides the "hidden variable" source regarding which axes the spins shall be restricted to; yet it does not immediately answer which particle will be up vs down. However, given the postulate that retro-causal effects are determined by the Principle of Least Action just as traditional causal effects are, isn't it possible that the measured spin itself is determined by the same principle? If one accepts the postulate it almost seems that one must accept a unique solution to "least action"*. I grant that we may never know the Least Action formulation, so claiming a Deterministic Universe may be unfalsifiable or even meaningless, but I believe that it may be possible to structure experiments that account for all advanced wavelike causes (including those that occur both after E and also after particle measurement at A and B)! Could I describe such an experiment? No, but I enjoy thinking about it.

* I know that mathematically this is not always true. I understand that a function may have more than one minimum but idealizations rarely apply to the real world.

Dmitry: My response to DrChinese is pertinent to your post as well. The Principle of Least Action postulate is not the heart of my interpretation but I feel it is valuable. Feynman's http://en.wikipedia.org/wiki/Path_integral_formulation" gives a unique solution to QM effects, so I don't feel like introducing it here is an overly radical thing to do.

The path integral formulation of quantum mechanics is a description of quantum theory which generalizes the action principle of classical mechanics.

 

[jsg]

This is a little off the track, but it seems to me that a parallel can be drawn between the collapse of the wave function and Descartes' "cogito." It works like this: Just as the collapse of the wave function reduces an infinite number of possible states to a single perceived one, so the "cogito"–"I think therefore I am"–reduces the infinite web of causality to a single agent, the "I" that does the thinking.

I find this interesting since neither the collapse nor the "cogito" cancels out the underlying possible states of the system on the one hand or the causal conditions behind an action on the other. But the parallel ends there since the collapse identifies an actual state while the "cogito" creates the necessary but misleading fiction of a single causal agent.

 

[alxm]

jsg, read the forum rules - don't highjack threads with off-base ideas.

 

[rjbeery]

Yes, that is interesting. My personal perspective, though, assigns nothing special to measurement or even knowledge in the quantum world beyond the principle of least action. As an analogy, the path that water "chooses" to flow down a mountainside is set before it makes its journey. There are not an infinite number of possible paths, but one, which is predestined (i.e. the path of least resistance). The measurement of a quantum system would be analogous to carving a trench at some point in the mountainside - yes, the water's flow does not remain unaffected by this but that does not give the measurement itself any more of an elevated status than the mountain's pre-existing topography had the trench not been dug...