Double slit experiment in 3 dimensions?

[weirdoguy]

How does this show that de Broglies equation is wrong?

How did you get that:

It says that when in an inertial reference frame that is at rest with object it always looks like a particle. And when in an inertial frame that is not at rest with the particle it looks like a wave.

in the first place? What does "look like a particle/wave" mean? I look at moving things and thet don't look like waves to me...

 

[bhobba]

When at rest with the particle there is no momentum so the equation states that the wavelength is infinite.

An infinite wavelength extending in all directions forever - the physicality of such is?

Note in QM such can't occur because of the uncertainty principle - but De-Broglie has no such restriction.

De-Broglie is a mishmash of the wave-particle duality and relativity that when pushed too far breaks down. Schrodinger realized this, and was spurred when someone asked him the obvious question - if its a wave it should obey a wave equation. He found one (but made an error although he got the correct answer - by dumb luck):
https://arxiv.org/abs/1204.0653

However analysis of the equation showed it did not do what he wanted it to do. It was shown to be equivalent to Heisenberg's Matrix Mechanics by a number of people, although they had issues of a technical nature. The first actual proof was from Von-Neumann. In the mean time an even more general theory was developed by Dirac at the end of 1926 called the transformation theory that generally goes by the name QM today. It contains nothing about wave-particle duality - but does contain things of dubious mathematical validity ie that damned Dirac Delta function. Von-Neumann in his famous Mathematical Foundations of QM was quite critical - it makes interesting reading. This spurred many of the greatest 20th century mathematicians to fix it up. They succeeded and now via so called Rigged Hilbert spaces is mathematically valid. The spin-off is the so called theory of distributions which has many many applications - not just QM - for example its the best way to do Fourier transforms. It can even handle the weird wave-function of infinite wavelength - but the answer is still the same - its nonphysical.

Thanks
Bill

 

[Karolus]

Why do beginner texts and popularization's not mention it - it will simply confuse beginners -

Even Feynman lectures on physics? So this is a book for beginners, only done to confuse; ... the wave-particle duality is here clearly expressed as one of the founding concepts of MQ. Or maybe it's a dated text that no longer worth reading?
(Too much of other texts, such as the Landau, all based on outdated misconceptions!)

If you don't like it stay with B level threads. You will still be told its wrong but much more gently.

This sounds a bit like a dogmatism, almost a truth of faith. Who does not accept it is a heretic. I do not think it's a truly scientific attitude.
However I accept willingly your objections, I will try to keep myself to the level of the thread to get me more modern and current knowledge of authors who treat the issue. (Though I note that we Off Topic, and turning you turn around you go to always end up on the same question: "what is quantum mechanics?" There who apparently has finally solved the problem and speaks with absolute certainty, but those who evidently still has doubts, or otherwise believes that the issue is controversial and not at all completed)

 

[mike1000]

An infinite wavelength extending in all directions forever - the physicality of such is?

Note in QM such can't occur because of the uncertainty principle - but De-Broglie has no such restriction.

De-Broglie is a mishmash of the wave-particle duality and relativity that when pushed too far breaks down. Schrodinger realized this, and was spurred when someone asked him the obvious question - if its a wave it should obey a wave equation. He found one (but made an error although he got the correct answer - by dumb luck):
https://arxiv.org/abs/1204.0653

However analysis of the equation showed it did not do what he wanted it to do. It was shown to be equivalent to Heisenberg's Matrix Mechanics by a number of people, although they had issues of a technical nature. The first actual proof was from Von-Neumann. In the mean time an even more general theory was developed by Dirac at the end of 1926 called the transformation theory that generally goes by the name QM today. It contains nothing about wave-particle duality - but does contain things of dubious mathematical validity ie that damned Dirac Delta function. Von-Neumann in his famous Mathematical Foundations of QM was quite critical - it makes interesting reading. This spurred many of the greatest 20th century mathematicians to fix it up. They succeeded and now via so called Rigged Hilbert spaces is mathematically valid. The spin-off is the so called theory of distributions which has many many applications - not just QM - for example its the best way to do Fourier transforms. It can even handle the weird wave-function of infinite wavelength - but the answer is still the same - its nonphysical.

Thanks
Bill

I think you avoided most of my question to you by creating a red herring. An infinite wavelength is the same as saying zero frequency. Zero frequency happens all the time, for instance, dc current is zero frequency.

I did not ask you about the Schrodinger equation. I asked you about the deBroglie equation.

 

[bhobba]

De Broglie's equation says that the product p*λ is quantized. Not p or λ individually, but the product p*λ. Are you saying this is not true either?

I think you need to review just what it says. Define quantized? Is the wave function of a free particle either in QM or De-Broglie quantized? Actual quantization is a very difficult issue as to why it occurs, but if you really want to know the following will explain it:


Thanks
Bill

 

[weirdoguy]

So this is a book for beginners

Of course it is. You didn't know that? Read first few pages, you'll find out for whom was the lectures made.

the wave-particle duality is here clearly expressed as one of the founding concepts of MQ

It is - but only in a historical sense. It's not conceptual foundation of 'modern' QM.

Too much of other texts, such as the Landau, all based on outdated misconceptions!

Where in Landau you find wave-particle duality as a foundation of quantum mechanics (Schroedinger equation, etc.)? I have all L&L books on my shelves, I read like 1/3 of QM one and I see no wave-particle duality there. How many QM books (not for the beginners) have you read? It's not about dogmatism, it's about facts. Facts that are quite easy to check.

 

[bhobba]

Even Feynman lectures on physics? So this is a book for beginners, only done to confuse

That is not what I said.

I said it needs to be built up to slowly like it was done historically, and that the way its usually done. I personally don't like it, but I don't teach or write text-books about it. I bow to those that actually do - they obviously do it because other appproaches are problematical.

I prefer:
http://www.scottaaronson.com/democritus/lec9.html

BTW Feynman knew of this issue, lamented it, but saw no other way.

Thanks
Bill

 

[DrClaude]

This thread has run its course. Time to close.