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I am not a physicist but i enjoyed the subject as a hobby and have my formal education in the field of computer science. If any of what follows is a big flaw in my understanding, I hope it will be forgiven.

The bottom line of my question is where does the two slit contradicts newtonian physics?

It has been done on photons, electrons and even small molecules resulting in patterns that suggest wave behaviour of those particles:

  • With photons the physical attributes of the pattern are connected to the frequency/energy of the emitted light, which is a wave with wavelength in 400-700nm, right?

  • With electrons and molecules is it (the pattern) not be related to the centripetal force exerted by the electrical respectively gravitational force applied on electrons/molecules by the edges of the slits (that have a certain crystalline structure)?

Also... why isn't refraction like the photo-electrical effect a proof that light is made also by quanta of energy (photons) that can act like a particle with electro-magnetic or even in the first case kinetic energy? Just because it contradicts math equations we are anyway unable to follow logically-what is the explanation on the refraction phenomenon?

Thank you for your patience with my profanity! I really hope that one day physics will meet logic again because otherwise I think that our understanding of this world will be put on hold.

Emilio Pisanty
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silviu
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  • http://physics.stackexchange.com/questions/158105/can-the-intensity-distribution-behind-edges-and-slits-be-explaint-by-the-interac – HolgerFiedler Jul 25 '16 at 20:25
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    One can demonstrate the phenomenon on surface waves on water, so it does not "contradict Newtonian physics": http://lightandmatter.com/html_books/lm/ch32/ch32.html. This also means that it tells us zip about photons or any other kind of quanta. It's a perfectly classical phenomenon. The first experiments that tell us something about field quantization are the Planck spectrum and the photoelectric effect. – CuriousOne Jul 25 '16 at 20:30
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    "I really hope that one day physics will meet logic again because otherwise I think that our understanding of this world will be put on hold." What was it, other than logic, that brought physicists to their current understanding of the world? Quantum mechanics isn't just an entertaining fiction made up so we could discuss how to kill cats. A century ago, physicists were dragged kicking and screaming into quantum mechanics. Who did the dragging? Nature. Reality. Our observations and experiments contradict every other story we've come up with. Nature does not care about human understanding. – Mark H Jul 30 '16 at 10:17

1 Answers1

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With photons the physical attributes of the pattern are connected to the frequency/energy of the emitted light, which is a wave with wavelength in 400-700nm, right?

Yes, with photons the double-slit pattern is not surprising, since photons are excitations of a specific mode of radiation and the modes obey the usual classical wave equation, which of course shows a double slit pattern. (Of course, that changes if you mess with the modes by putting which-way detectors, which then get entangled with the field.)

With photons the contradiction comes because on top of this usual classical wave understanding they can also behave as particles (such as having only discrete detections with a sensitive enough photodiode), but to get to stuff that's really hard to explain with classical models you need to use things like Mandel dips; photons are not "particles", they're discrete excitations in the amount of energy in a mode of radiation, and it's mostly when you get to counting statistics (how often there is how much energy in the mode) that you step definitively outside of classical models.

With electrons and molecules is it (the pattern) not be related to the centripetal force exerted by the electrical respectively gravitational force applied on electrons/molecules by the edges of the slits (that have a certain crystalline structure)?

No. There is just no credible way to imagine that the electrical interactions between material particles and the slits will produce the observed behaviour, particularly when you require the pattern to maintain its shape but change its fringe width when you change the particles' energy and thereby their de Broglie wavelength. There's just no Newtonian models of interactions that have stood up to experiment here.

As to your other comments, refraction is a wave phenomenon but it does admit explanations using particle models (going as far back as Newton's Opticks, though not without their problems), but generally refraction is not thought of as a problematic phenomenon - it is perfectly well explained by the wave theory of light. The photoelectric effect, on the other hand, is indeed a strong piece of evidence of why light acts as a particle.

Finally,

Just because it contradicts math equations we are anyway unable to follow logically

is not a viewpoint I share. There is no requirement that Nature's laws be fully accessible to human understanding (though it would be nice). Quantum mechanics can be counterintuitive indeed, and it would be nice to have a theory that was more suited to our classically-honed intuition, but I don't think there's a requirement on nature to oblige.

Generally, the "math equations" is a bad way to put it: it is a solid theoretical framework with many experimental predictions and interconnections which have been verified in the real world, and there isn't anywhere near a suitable replacement to be seen. Quantum mechanics does have (rather deep) conceptual problems, most of them congregated around the measurement problem and the fact that we do not yet have a fully unambiguous and consistent way to set the postulates of QM in a manner that does not rely on an external distinction between what does and does not follow quantum mechanics (or what does and does not cause a wavefunction collapse). However, phrasing this as a hope that "one day physics will meet logic again" is very far from a constructive way to phrase things.

Emilio Pisanty
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  • Nice answer. I'd like to emphasize the comment " There is no requirement that Nature's laws be fully accessible to human understanding ." Eventually, every law comes down to some unexplained assumption. But more to the point, it seems to me that the fact that the human brain evolved in a macroscopic environment may have as a consequence that it is not capable (at the moment) to understand the microscopic world of quantum mechanics. – garyp Jul 30 '16 at 10:59