Einstein's View of Quantum Mechanics

[bhobba]

Even for me this is a bit simplistic. There has been an infinity of bad experiments, if you include the social sciences then the cardinality is c. Recently the Italians showed the relativity guess was wrong, since neutrinos go faster than light. And speaking of infinity,

Infinity - but I get your drift - and yes you are correct.

His proof involves infinite sequences of r.v.s, which is what I thought you want to avoid.

Yes - of course. Sorry I wasn't clearer - it's just an example of the only one I know - I do not know how to avoid infinite sequences. I will need to study your link to find out how its done.

Thanks
Bill

 

[bhobba]

It is not testable whether decoherence provides the answer. That the combined system of photon and device satisfy the deterministic unitary evolution of QM is all well and good, yet like a classical coin flip no one can predict the outcome so it is modeled stochastically.

Of course it isn't - like all interpretations.

It is testable, and has been tested, that decoherence exists.

Thanks
Bill

 

[Zafa Pi]

You are correct in saying sometimes it seems like a particle, and sometimes it seems like a wave. To be even plainer - there is nothing wrong with it at all. But that isn't what the above says - especially the bit: in some experiments both of these complementary viewpoints must be invoked to explain the results. It never needs to be invoked - period.

And I said, "Wave-particle duality to me is that some measurements of a photon make it seem wave like and other measurements make it seem particle (bullet) like. For instance, the double slit experiments. Admittedly, I don't know what it means to say a photon is simultaneously both a wave and a particle." So we are in agreement, and I agree with the rest of what you said.

When I tell an acquaintance I am interested in QM and they respond with, " Oh yeah, an electron can be a wave and particle at the same time." I come back with: The 1st amendment of the US constitution permits you to say that, and you can also say an electron can be in two places at the same time, and that QM justifies ESP, and the world is flat. But you will not find any of those statements in any QM text that I know of.

I do not know how to avoid infinite sequences. I will need to study your link to find out how its done.

I think Nelson wrote a beautiful book. When some asks me what is probability theory I tell the to read the 1st 8 pages of Nelson. He accomplishes finiteness via an elegant treatment of non-standard analysis.

 

[zonde]

Of course it isn't - like all interpretations.

It is testable, and has been tested, that decoherence exists.

Decoherence as a loss of visibility of interference effect is of course observable effect (usually undesirable).
But when you argue for emergence of classical reality from fundamental wavefuncion using decoherence, it is part of the interpretation.

 

[vanhees71]

Of course it isn't - like all interpretations.

It is testable, and has been tested, that decoherence exists.

Thanks
Bill

I'd put it the other way: To the dismay of quantum-computing afficionados it's quite difficult to avoid decoherence! That's the reason, why almost everything around us at a superficial glance looks as if it were behaving perfectly according to classical physics. Of course, if one knows about the compositeness of matter out of charged quanta, it becomes very clear that already the stability of matter, which only makes our own existence possible in the first place, is only understandable by QT (most importantly the fact that the constituents of matter, quarks and leptons, are fermions and thus behave according to the Pauli exclusion principle and Fermi-Dirac statistsics). The apparent classicality of macroscopic bodies is apparent and due to the fact that the relevant observables for such classical macroscopic systems are very much coarse-grained quantities, averaged over quite "large" (from a microscopic point of view) regions of space and also quite "large" time intervals. That's thanks to a separation of scales, separating the typical length scales and relaxation times of these macroscopic coarse-grained observables on the one hand and their quantum (and thermal) fluctuations on the other hand.

 

[vanhees71]

I wrote, "Wave-particle duality to me is that some measurements of a photon make it seem wave like and other measurements make it seem particle (bullet) like. For instance, the double slit experiments. What's wrong with that? Admittedly, I don't know what it means to say a photon is simultaneously both a wave and a particle."

There's nothing wrong with that, but it is overcomplicating things. Wave-particle duality is a notion of the socalled "old quantum theory" which AFAIK none of the "founding fathers" of QT ever took as "the final word". Einstein always emphasized after his photoelectric paper of 1905 that he cannot stop thinking about the problem (!) of understanding radiation. He even thought it's the far more challenging problem than his General Theory of Relativity.

IMHO these difficulties are overcome with the discovery of modern QT with Born's achievement of the probability interpretation of the quantum state as the key to the resolution of all mindboggling contradictions and inconsistencies of the old wave-particle-duality handwaving. According to moder QT neither a classical particle nor a classical field (or wave) description is a complete picture (in relativistic QT even a wave-mechanics picture a la Schrödinger's non-relativistic QT representation is impossible!). A quantum is a quantum. You cannot explain it by simpler ideas than QT itself. QT is today the fundamental theory of how matter and fundamental interactions are described. It cannot be reduced to something even more fundamental. Maybe that's possible in the future with even better and more fundamental theories, which might be discovered by some genius.

In you photon example, it's clear that the photon is the one freely moving quantum that has the least particle-like properties ever. It doesn't even let's you define a position observable in the strict sense, i.e., said in an operational way, you cannot localize it. All you can do is to calculate the detection probability of the photon at the localization of you detector. That's all that QED provides you, and so far there's no necessity to seek for something else than QED!

 

[bhobba]

I tell the to read the 1st 8 pages of Nelson. He accomplishes finiteness via an elegant treatment of non-standard analysis.

Non Standard Analysis ie ultrafilters and all that, that takes me back. I understood it - with difficulty - the math was HEAVY. The results without the proofs etc inst too bad.

Thanks
Bill

 

[Dale]

Closed for moderation

 

[Evo]

Closed