I Wave-particle duality: nature of wave-particle as it travels

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Ahhh! I see. So the energy of the EM wave must first "become" a photon and then the detector detects it?
I must admit I hesitated to use the word "transfer". I would have rather used he word "convert."
There is no conversion. And it does not matter if you call it conversion, transfer or whatever. Nothing like that is happening.
OK, so would this suggest that we really just don't know yet? Per option #4, we need to figure out a way to actually measure the behavior, gain THAT knowledge, and go from there?
We cannot know, and you can prove that we cannot know because it has no impact on any measurement we can make. You can simply pick your favorite interpretation. You can also start endless discussions, but those tend to be pointless.
What I meant was from the moment that the electron is incident upon a potential barrier and starts to tunnel, to the moment it "appears" on the other side of the barrier. Is that time interval equal to zero, or does it have some finite value? A. Neumaier suggested that it was non-zero but that it was controversial.
Those times are not well-defined in the same way the position is not well-defined. The wave front cannot propagate faster than the speed of light.
 

vanhees71

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Hi,

Three sentences that will keep me studying for a long time just to truly understand. But I ask, confirmed how? Empirically?

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The violation of Bell's inequality in ever more sophisticated experiments is a very hot topic in the quantum-optics/AMO community. The good thing is that you can understand the basic principles with very simplified models, using only finite-dimensional unitary spaces (although one must be careful with the interpretation, particularly with respect to the space-time picture of such experiments, because usually one cuts away the spatio-temporal aspects by just concentrating on the spin states/polarization states under investigation). A quite nice example you can find here, discussing an experiment that's suitable for the undergrad labs at universities (according to the authors):

http://arxiv.org/abs/quant-ph/0205171
 
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Hi,

Thanks for all the input!

That's pretty much the challenge that Einstein and his collaborators laid down in the 1935 EPR paper: http://www.drchinese.com/David/EPR.pdf
Excellent. Downloaded and sitting on my desktop to read! Thank you.

Thus, we have to take seriously the disconcerting possibility that there is no underlying behavior there to measure and #4 really is the way the world works - it's not a call to action but a "road closed ahead" sign.
This somehow makes me sad as exploration is in my heart and a "road closed sign" means an end to further exploration... unless of course you ignore the sign. But I guess one does so at their own peril.

There are a bunch of threads on this question over in the relativity subforum. The answer that is most in the spirit of your question is that the speed of light follows from the properties of electricity and magnetism - you can calculate it from Maxwell's equations in a manner analogous to the way that you calculate the speed of ocean waves from the known fluid dynamics of water. Indeed, Maxwell did exactly that in 1861
(I will caution you that this formulation is not consistent with the best modern approach to deriving the behavior of light, but that's a digression here. You can read through the threads in the relativity forum if you want more).
Yes, you are right... a question more for suitable for the relativity section. I thought I saw something in Schrodingers equation that might yield a different way to look at it or some sliver of insight that relativity was not giving us and so I decided to approach this whole thing from QM rather then relativity. It appears that I may have been wrong however. I will go over and read up at the relativity section as you suggest.

He wasn't exactly wrong, but that does fall in the category of "Lies to children undergraduates" (https://en.wikipedia.org/wiki/Lie-to-children). There's a fascinating chapter in Ballentine where he identifies the basic principles which lead to Schrodinger's equation. Ballentine is not an undergraduate text, but it is indispensable if you want to understand QM at a level beyond what your professor was giving you.
I'm actually glad to hear this. There is sure a lot more to this story then I understood coming out of undergrad. Nothing is EVER as simple as it appears is it! Ballentine. OK, probably way beyond me at this moment but it is saved and I'll get there one day. Thanks very much for pointing me in the directions that you have.

There is no conversion. And it does not matter if you call it conversion, transfer or whatever. Nothing like that is happening.
We cannot know, and you can prove that we cannot know because it has no impact on any measurement we can make. You can simply pick your favorite interpretation. You can also start endless discussions, but those tend to be pointless.
Ok, ok. I'm beginning to understand that in order to understand what I want to understand I need a much higher level of understanding (how's that for a sentence!). This is part of my learning process and it will take me time to even come close to your level. I agree that discussions can be or get pointless but nothing here to me is at that point. Everything that everyone has said here has helped me LEARN, which is what I'm after. I'm after the reality of things, not fantasy... I'll get there eventually. This discussion has helped me learn a lot and your input has also helped, I thank you.

The violation of Bell's inequality in ever more sophisticated experiments is a very hot topic in the quantum-optics/AMO community. The good thing is that you can understand the basic principles with very simplified models, using only finite-dimensional unitary spaces (although one must be careful with the interpretation, particularly with respect to the space-time picture of such experiments, because usually one cuts away the spatio-temporal aspects by just concentrating on the spin states/polarization states under investigation). A quite nice example you can find here, discussing an experiment that's suitable for the undergrad labs at universities (according to the authors):

http://arxiv.org/abs/quant-ph/0205171
Ok great! Thank you. I was wondering where to start with that.


OK, so I now have so much to do and read and learn that it seems that is where I need to go from here. This has been a great discussion and it has achieved exactly what I wanted, which was an education in the (current) thinking concerning QM and relativity and it has allowed me to assess my current working understanding of physics and where I need to start! Remember, every journey starts with the first step. You'll see me around asking much more mundane but practical questions like "what is wrong with my math here?" or "what the heck does this symbol mean?" or "How do I go about solving this or proving that?". Thank you all again!

Peter

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Peter99 wrote: "The solutions to Shrodingers equation necessarily contain i and this is quite hard for us to understand in a physical way (and indeed, i is mathematically undefined)."

David Lewis wrote: Any number* divided by zero is mathematically undefined. As far as a practical application of i, it comes in handy when you want to rotate vectors.

*Other than zero.
 
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I think what I was asking was WHY do electric, magnetic, gravitational, and other (space-time?) fields as well as mass-less particles propagate/travel at the speed of light? I was looking for a more fundamental understanding of this.
The symmetries of an inertial frame:
http://www2.physics.umd.edu/~yakovenk/teaching/Lorentz.pdf

This all by itself implies the existence of an invariant speed - it may be infinity. If it was infinity that would actually be rather weird - it would mean if I did something here on earth it could instantaneously affect something at the other side of the universe. This is not what we experience in our day to day life - we don't see things around us is affected by things light years away instantaneously. A finite speed simply determines a fundamental constant of nature and is given the name of C. The question isnt why do massless particles, em fields etc travel at the speed of light - the question is why do they travel at that invariant speed . Since light is EM waves obviously that is the speed of light. But I stress its a consequence of the fundamental property's of space-time implied by symmetries.

Thanks
Bill
 
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(and indeed, i is mathematically undefined)
It has a well-defined mathematical description.
it would mean if I did something here on earth it could instantaneously affect something at the other side of the universe. This is not what we experience in our day to day life - we don't see things around us is affected by things light years away instantaneously.
It would not change much if we ignore the effects on particle physics and cosmology. You would instantly be affected by the current locations of the stars in Alpha Centauri - so what? We are influenced by their positions approximately 4 years ago, but we do not care because that influence (and, in particular, its change over 4 years) is negligible.
 

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