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dkgolfer16
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Since QT violates SR is it safe to say one of the former will be disregarded / revised in the future? See EPR paradox.
dkgolfer16 said:Huh? I never said EPR violated SR. EPR isn't a theory its a paradox...
jtbell said:Quantum electrodynamics (QED) is fully (special-)relativistic.
dkgolfer16 said:Sorry I'll explain further. Take two particles A and B. The spin of A is unknown until we measure it. When we do measure the spin of A, B's spin wave function then instantaneously collapes to the opposite state. This transaction occurs faster than the speed of light, violating SR.
Maaneli said:But I'll just say that in the way you formulated the problem, there is no experimentally observable violation of SR since SR only prohibits superluminal matter and energy transport.
dkgolfer16 said:So you're saying SR allows particles to travel faster and communicate at speeds that exceed c? Last time I checked this is a violation of SR so before answering your questions maybe you could elaborate and explain.
dkgolfer16 said:Using textbook QM, Bell's inequality results in non local interactions taking place between particles. Do these non local interactions, which take place at speeds greater than c and in which distance does not effect interaction speed, have no consequence on what SR tells us?
Maaneli said:But textbook QM, being only a statistical formalism, can only describe this nonlocality in terms of correlations, since it does not describe what the underlying physical causes those nonlocal entanglement correlations are.
dkgolfer16 said:Thanks Maaneli. Your answer makes sense and I look forward to going through the attached suggested reading material you presented. One last question.
So based on textbook QM (the others I admit I have to become more familiar with), because it cannot describe the underlying physical causes of these nonlocal entanglement correlations, we can safely say a conflict does exist between textbook QM (with its nonlocality) and SR (with its constant in all frames speed of c)?
It is different, but actually, and interestingly, I think, one of Einstein's very first challenges to Bohr in their famous exchanges was something along the lines of: "You say the wavefunction evolves and expands out to give a distinct probability of detection at every point on the detector. How does each point on the detector "know" instantaneously that the particle has finally been detected in only one space?It should also emphasize that the textbook QM postulate of instantaneous "collapse of the wavefunction" is different from the nonlocality in the entanglement correlations, since the nonlocal entanglement correlations between the two particles can be expressed without any mention of the quantum mechanics of entangled wavefunctions
I have, then I read the answersZapperZ said:Did you read this?
http://arxiv.org/PS_cache/arxiv/pdf/0704/0704.2038v1.pdf
and this?
http://arxiv.org/abs/quant-ph/0703218v1
Zz.
What has been peer-reviewed ? I know it was submitted, but was it published ?peter0302 said:Wow. How does stuff like that get missed in peer review?
peter0302 said:FTL information exchange does violate SR but, as pointed out, is not possible in any interpretation of QM.
peter0302 said:Moreover, if realism is disregarded (see, e.g., MWI), there is no FTL problem at all.
peter0302 said:If an FTL influence were ever unambiguously discovered, it would be a breakthrough for physics, but both QM and SR would likely survive unscathed.
peter0302 said:Bohr's ultimate solution was essentially to say that it doesn't matter, because the wavefunction is just a tool for predicting experiments, and not necessarily a physical entity, and hence was born the Copenhagen Interpretation.
Ok, now that statement is just totally unsupportable. What was an inadequate riposte was the naive belief in hidden variables, which was never something Bohr or Heisenberg were proponents of. Many people disliked Bohr's published response to EPR as missing the mark, but his and Heisenberg's core arguments which eventually became CI are still running strong.With the advent of Bell's theorem, it became clear that Bohr's proposed solution was an inadequate riposte.
peter0302 said:Ok, now that statement is just totally unsupportable. What was an inadequate riposte was the naive belief in hidden variables, which was never something Bohr or Heisenberg were proponents of. Many people disliked Bohr's published response to EPR as missing the mark, but his and Heisenberg's core arguments which eventually became CI are still running strong.
peter0302 said:I never said Bell was naive. I said that Bell disproved a naive view of hidden variables.
peter0302 said:And by the way, I have read the Bell papers in the very book you like to quote. And I also know that Bell was a fan of DeBroglie-Bohm, although not quite as dedicated as you appear to be.
peter0302 said:I have to say your posts are really getting oddly personal - even by this board's standards. Really quite unnecessary.
humanino said:Hey guys, instead of arguing, can you help me out and tell me something like "no Clifford valued operator can be hermitian, thus observable", so you'll pull me out of confusion
edit
true it has not been published, but true as well it has been posted on the arXiv by a decent physicist
peter0302 said:What I can tell you is that the Bell view that you can't have locality and realism in the same theory has not yet been disproven.
peter0302 said:I also recall a number of papers cited here suggesting that even non-local, realistic theories don't hold up either, taking Bell a step further.
humanino said:Hey guys, instead of arguing, can you help me out and tell me something like "no Clifford valued operator can be hermitian, thus observable", so you'll pull me out of confusion
edit
true it has not been published, but true as well it has been posted on the arXiv by a decent physicist
Never mind, as Zz indicated this should strictly not have been posted here. I will have to wait and see if he finally manages to publish. But if he does not, then I will not have any "official" rebuttal. I'm not sure whether the problem is with his definition of observable or locality, or both...Maaneli said:Sorry man, I don't know anything about this yet. It looks interesting, but it'll take me some time to say anything useful.
Actually, I do have a very similar point. By definition, a Clifford valued quantity is not a real valued quantity, so it cannot be observable.humanino said:Hey guys, instead of arguing, can you help me out and tell me something like "no Clifford valued operator can be hermitian, thus observable", so you'll pull me out of confusion