A question about quantum entanglement

[Matterwave]

Well, there are always debates about the best way to formulate a theory from basic principles (see the reference above to Höhn's article).

Lucas.

You can certainly debate anything, but SR is generally formulated on the constancy of the speed of light and the equal validity of all inertial frames of reference ("relativity principle"). This was given by Einstein in 1905 and I don't see a ton of debate on trying to change that. Time dilation is a consequence of those 2 postulates.

 

[Fra]

I disagree: we do understand why there is the phenomena of time dilation in special relativity.

You can certainly debate anything, but SR is generally formulated on the constancy of the speed of light and the equal validity of all inertial frames of reference ("relativity principle"). This was given by Einstein in 1905 and I don't see a ton of debate on trying to change that. Time dilation is a consequence of those 2 postulates.

Of course, we can explain time dilation, cleanly and logically from the postulates, since 1905. Few theories are as clear and clean as SR.

But the conceptual problem still today is that while the no preferred observer is extremely intuitive. The light postulate, while technically simple, is by no means obvious or intuitive. But any debate on that, would not be of the form that the postulated is "wrong" in the validated experimental domains, it would likely be that maybe it can be formally relaxed and that it's "status" of postulate or axiom, could be REPLACED by some evolutionary principle or some attractor, based on some other principles that are in fact as intutive as the no preferred observer principle. That would bring deeper understanding, not just a reformulation into "new variables". But so far this is not existing as mature science. This is what i referred to.

/Fredrik

 

[Fra]

and maybe Barandeis "spooky action at a time" (indivisible non-markovian processes). Though I don't know how "well established" they are.

I agree with this hook. This was discussed in other threads. Barandes is making good contributions, but the picture he provides is critically incomplete still to serves as a resolution. The specific part is a missing first principle new reconstruction of the transition probabilitites (gamma). So far, they are only inferred from the hilbert picture via the correspondence. The gamma matrices hides the mystery, to complete the resolution, I think we need to explain how the gamma matrices evolve; my I see all possibilities for his program to be completed in that way. But that is also not on the table yet.

/Fredrik

 

[Sambuco]

You can certainly debate anything, but SR is generally formulated on the constancy of the speed of light and the equal validity of all inertial frames of reference ("relativity principle"). This was given by Einstein in 1905 and I don't see a ton of debate on trying to change that. Time dilation is a consequence of those 2 postulates.

Sure, that's precisely why I said that no one is looking for an underlying mechanism to "explain" time dilation in special relativity!

This does not happen in quantum mechanics, where the prediction of entanglement and the violation of Bell's inequalities are not usually accepted at face value, but rather an additional mechanism is sought to "explain" it.

Lucas.

 

[PeterDonis]

no one is looking for an underlying mechanism to "explain" time dilation in special relativity!

the prediction of entanglement and the violation of Bell's inequalities are not usually accepted at face value, but rather an additional mechanism is sought to "explain" it.

I think the difference here is that time dilation in SR is not an observable--it's something that's calculated by assuming a particular inertial frame. The actual observable is the relativistic Doppler shift. I don't think people just accept the relativistic Doppler shift without looking for some kind of underlying mechanism.

Similarly, in the case of QM, Bell inequality violations are an observable, so people want to look for an underlying mechanism.

 

[Fra]

Elevating something to a postulate or axiom, means that within the theory, it is something you do not further need to explain. But a theory (regardless how well corroborated it is) is never more intuitive or understandable than the plausibility of it's the postulates it rests on. As I see it postulates is a form of hidden implicit fine tuning of the "theory space", which is at theoryspace level rather than fine tuning initial conditions within a given dynamical system.

The light postulate is not intuitively obvious in SR.

In QM there are also several non-intuitive postulates/axioms, introducting hilbert spaces and perhaps worst, the time evolution postulates of the hamiltonian operator for a close system. There is a huge amount of what i conceptually see as "fine tuning" hidden in the hamiltonian and the hilbert space structure.

Just like I advocate naturalness in initial conditions, the ambition is tha a good theory should be built in at least reasonable postulates as well, that is ideally intutitive.

One excellent example, that is one foundational postulate is the "no preferred observer" or "no preferred frame". That is I think something that most would agree is indeed plausible, as the opposite would simple be unnatural and required an explanation.

Alot of other things, have a long way to reach that level of plausibiliity.

/Fredrik

 

[Morbert]

As an aside: There are analogous interpretational debates around special and general relativity. See e.g. substantivalist vs relationalist spacetime, or kinematical vs dynamical/neo-Lorentzian accounts. I suspect they are not as energetic as QM debates because relativity doesn't assault our notion of a primitive ontology to anywhere near the same degree.

 

[FactChecker]

The light postulate is not intuitively obvious in SR.

After precise experiments that measured the speed of light as c, no matter what the velocity of the test platform was, I think it was somewhat natural to consider.

 

[Sambuco]

I think the difference here is that time dilation in SR is not an observable--it's something that's calculated by assuming a particular inertial frame. The actual observable is the relativistic Doppler shift. I don't think people just accept the relativistic Doppler shift without looking for some kind of underlying mechanism.

Similarly, in the case of QM, Bell inequality violations are an observable, so people want to look for an underlying mechanism.

Interesting! I'd never thought of it that way.

Lucas.