Xray wrote:AFAICT, the Bertlmann chapter is complete.
But the eBook here is Bell (1987), not Bell (2004). So the opening reference to Alain Aspect is, to me, misleading.
The eBook page numbers are 10 higher that the hard-copy because the hard-copy numbers the Preface etc (i) to (x). The eBook numbers them 1-10.
HTH, Xray
jreed wrote:These arguments about the screen assembly are exactly what Stopes-Roe was writing about in his Nature article. He couldn't understand how the screen assembly was acting as a whole. Lande gave a reply to this, but he just said essentially that an understanding of it will probably appear at some time in the future. I don't believe this. To use phonons to explain it will depend on the bulk modulus of the material, thickness, mounting rigidity and many other things. The diffraction pattern, on the other hand only depends on the width of the slits and the distance between them. As I said when all this started, this theory just moves the trouble (interference patterns) from the electrons, where it is calculated using the wave function obtained by solving Schroedinger's equation to the slit assembly. Now the interference calculation has been moved to another place, the screen, where it must again be found using quantum principles (phonons are quanta of the mechanical assembly). I don't find either theory more locally realistic. What has been gained?
gill1109 wrote:Seems to me they should each be cut in a separate piece of (whatever) and the two pieces should be slightly separated and mounted on such a sturdy frame that vibration can hardly move from one half to the other half.
Ben6993 wrote:Following on from the idea of using soft curtains, a different idea is to connect the slits to vibrators and so apply random noises to the slits. Increasing the strength of the noise should decrease the sharpness of the interference pattern if the pattern is affected by linear momentum transfer at the slits. (This surely has already been tried?)
jreed wrote: Lande gave a reply to this, but he just said essentially that an understanding of it will probably appear at some time in the future.
I don't believe this. To use phonons to explain it will depend on the bulk modulus of the material, thickness, mounting rigidity and many other things.
The diffraction pattern, on the other hand only depends on the width of the slits and the distance between them.
As I said when all this started, this theory just moves the trouble (interference patterns) from the electrons
Now the interference calculation has been moved to another place, the screen, where it must again be found using quantum principles(phonons are quanta of the mechanical assembly). I don't find either theory more locally realistic. What has been gained?
minkwe wrote:Ben6993 wrote:Following on from the idea of using soft curtains, a different idea is to connect the slits to vibrators and so apply random noises to the slits. Increasing the strength of the noise should decrease the sharpness of the interference pattern if the pattern is affected by linear momentum transfer at the slits. (This surely has already been tried?)
Not as far-fetched as you may think. You have to apply the right vibrations though not just any type of vibrations. And indeed this has been done, (in a crystal), by adding forced vibrations, new diffraction peaks appear. I'll dig up the article.
We simultaneously measured the momentum transferred to a free-floating molecular double slit and the momentum change of the atom scattering from it. Our experimental results are compared to quantum mechanical and semiclassical models. The results reveal that a classical description of the slits, which was used by Einstein in his debate with Bohr, provides a surprisingly good description of the experimental results, even for a microscopic system, if momentum transfer is not ascribed to a specific pathway but shared coherently and simultaneously between both.
jreed wrote:But, on this same web site, there are the following two paragraphs:
"A particle passes through a single slit and then through one opening of a double slit. Can the pathway of the particle be determined without destroying the interference structure? This was a question first debated by Einstein and Bohr as they tried to understand the newly developed ideas of quantum physics. Einstein argued that classical physics was sufficient; you could determine the particle’s path by measuring the momentum transfer imparted from the deflection of the particle by the first slit. Bohr claimed instead that the slits, as well as the particle, behave as quantum objects, whose position and momentum are uncertain—we can either know which path the particle takes through the slit maze, or how long the path is, but not both.
So who was right? Writing in Physical Review Letters, Lothar Schmidt and colleagues, from Goethe University in Germany, show that Bohr was right. In their experiments, the team replaced the slits with hydrogen-deuteron molecular ions and bombarded them with helium atoms. As the atoms collided with the ions, an electron was exchanged between the atom and the ion. By measuring this exchange they could determine the positions and orientation of the atoms and ions. The scattering of the atoms was consistent with Bohr’s view; you need a quantum description of the slits and particles to understand the results. However, the results could still be correctly predicted using classical slits, but only if the particle simultaneously passed through both holes of the double slit and transferred half of its momentum to each path. – Katherine Thomas"
minkwe wrote:
Their results show clearly that. diffraction is a momentum transfer phenomenon, contrary to what some people continue to believe.
jreed wrote:minkwe wrote:
Their results show clearly that. diffraction is a momentum transfer phenomenon, contrary to what some people continue to believe.
Do you have a copy of this paper? I'd like to get a closer look at it so I could understand what they did better.
gill1109 wrote:jreed wrote:minkwe wrote:
Their results show clearly that. diffraction is a momentum transfer phenomenon, contrary to what some people continue to believe.
Do you have a copy of this paper? I'd like to get a closer look at it so I could understand what they did better.
Yes, but is it a classical momentum transfer phenomenon or a quantum momentum transfer phenomenon?
jreed wrote:jreed wrote:I'm sure it will be momentum transfer by Duane's quantum rule. Does anyone have a copy of this paper, or is Minkwe so sure of his theory that he can dismiss the synopsis of Katherine Thomas as being wrong without knowing any of the details of the experiment or the theory behind it?
jreed wrote:
Yes, that's the one. Thanks very much for the reference. Maybe this will make this experiment easier to understand and sort out the differing theoretical approaches.
Schmidt et al wrote:We simultaneously measured the momentum transferred to a free-floating molecular double slit and the momentum change of the atom scattering from it. Our experimental results are compared to quantum mechanical and semiclassical models. The results reveal that a classical description of the slits, which was used by Einstein in his debate with Bohr, provides a surprisingly good description of the experimental results, even for a microscopic system, if momentum transfer is not ascribed to a specific pathway but shared coherently and simultaneously between both.
Schmidt et al wrote:As an alternative to a quantum mechanical description of the slits, our results show that a classical description of the slits according to Einstein’s original viewpoint of the thought experiment is still possible. In that case one has, however, to assume a delocalized nonclassical interaction.
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