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Double Slit Experiment No Mystery

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Re: Double Slit Experiment No Mystery

#61

Post by ryanthedev »

coldtea wrote: post #43
ryanthedev wrote: post #39

Earlier quoted context omitted.

Well I don't believe that's what he intended. It seemed he was trying to argue about the double slit not being evidence of wave particle duality. I tend to agree, the notion of matter being in two places at once is nonsense. Also I agree with the author that the majority of people tend to point to the double slit as some type of proof.

> I tend to agree, the notion of matter being in two places at once is nonsense. Based on what? Empirical experience with macroscopic objects? There are tons of phenomenons that are at odds with everyday empirical experience for that to matter (relativity has all kinds of such cases).

Based on the fact that no two reference frames are the same.

Based on the fact that everything points to the universe being deterministic.

Also we have never been able to even prove it mathematically.

Re: Double Slit Experiment No Mystery

#63

Post by egdod »

ryanthedev wrote: post #52
z92 wrote: post #7

Actually the mysteries are deeper. This one can't explain "Delayed Choice Quantum Erasure" experiments, which is also a double slit experiment. But the arrangement allows you to detect the path AFTER the photon has traveled through one of the slits and hit the surface. Now after the photon has hit the surface you can decide whether to detect its path or not. A delayed choice. But based on your later choice the interf…

The quantum Erasure doesn't have anything to do with wave particle duality imo. They are purely testing the effects of entanglement and choice. I see entanglement differently than most people. They tend to believe it's a state of identically positioned particles acting in unison. To quote the wiki "that converts the photon (from either slit) into two identical, orthogonally polarized entangled photons with 1/2 the fr…

Not even wrong.

Re: Double Slit Experiment No Mystery

#64

Post by vincent-toups »

knzhou wrote: post #51
lisper wrote: post #49

Earlier quoted context omitted.

> committing to a classical ontology in terms of "waves" or "particles" is almost impossible Not that I disagree with this, but I'd like to hear what you have to say about de-Broglie-Bohm.

de Broglie-Bohm has the same problems as usual for such theories. I wrote an article once [0] about such things and I'll just quote from it. > To understand the working physicist’s position, it is useful to consider pilot wave theory. This alternative to the Copenhagen interpretation is often championed by realist philosophers, who would prefer that measurable properties, such as the position of a quantum particle, s…

This is as good a description of the ontological limitations of pilot wave theory as any, but many of the criticisms apply to almost literally any interpretation of quantum mechanics whatsoever.

As a physicist with a passing interesting the subject of foundations, its my feeling that what quantum mechanics tells us is that at least one aspect of our classical ontologies is not correct. My personal bet is that its locality which is the problem, but as far as I understand it the question is still wide open.

de Broglie-Bohm merely casts the ontological tensions with classical physics in one particular light, but I'm aware of no interpretation which is free of the tension.

Re: Double Slit Experiment No Mystery

#66

Post by didgeoridoo »

knzhou wrote: post #44

Physicist here. This is just self-congratulatory nonsense. Though I shouldn't be surprised, because I originally signed up for this site to comment against some other self-congratulatory nonsense. Quantum mechanics is built on extraordinarily simple rules, in fact simpler ones than classical mechanics: all you do is sum up the amplitudes for various paths, and square it to get a probability. The problem is that the o…

> the classical variables would have to either influence each other faster than light, or be pre-set since the beginning of the universe in a malicious conspiracy

Why is superdeterminism almost universally rejected by working physicists? From the outside, it feels like the most parsimonious explanation: there is just a single way things are and will be, set in motion from the very beginning. It doesn’t feel like a conspiracy of any kind to me.

I’m definitely missing something, but what?

Re: Double Slit Experiment No Mystery

#67

Post by olliej »

The author has gotten confused the bit about the double slit experiment that is “mysterious”.

The mysterious bit isn’t what happens when you transmit a stream of particles.

It’s what happens when you only send one at a time. If the movement was purely changes to particle momentum you would get a uniform spread across your detector.

But that’s not what happens. What happens is you get a diffraction, that only makes sense if your particle goes through both slits.

Re: Double Slit Experiment No Mystery

#69

Post by [deleted] »

knzhou wrote: post #51
lisper wrote: post #49

Earlier quoted context omitted.

> committing to a classical ontology in terms of "waves" or "particles" is almost impossible Not that I disagree with this, but I'd like to hear what you have to say about de-Broglie-Bohm.

de Broglie-Bohm has the same problems as usual for such theories. I wrote an article once [0] about such things and I'll just quote from it. > To understand the working physicist’s position, it is useful to consider pilot wave theory. This alternative to the Copenhagen interpretation is often championed by realist philosophers, who would prefer that measurable properties, such as the position of a quantum particle, s…

[deleted]

Re: Double Slit Experiment No Mystery

#70

Post by knzhou »

didgeoridoo wrote: post #66
knzhou wrote: post #44

Physicist here. This is just self-congratulatory nonsense. Though I shouldn't be surprised, because I originally signed up for this site to comment against some other self-congratulatory nonsense. Quantum mechanics is built on extraordinarily simple rules, in fact simpler ones than classical mechanics: all you do is sum up the amplitudes for various paths, and square it to get a probability. The problem is that the o…

> the classical variables would have to either influence each other faster than light, or be pre-set since the beginning of the universe in a malicious conspiracy Why is superdeterminism almost universally rejected by working physicists? From the outside, it feels like the most parsimonious explanation: there is just a single way things are and will be, set in motion from the very beginning. It doesn’t feel like a co…

Because if you take superdeterminism seriously, you can't do science.

Sure, it is logically possible that the world runs on classical mechanics, but that random factors in the light emitted from opposite ends of the observable universe billions of years ago were delicately set at that point so that whenever you run an experiment with it, naively assuming that no such correlations exist, quantum mechanics appears to be true instead.

Unfortunately, if you are consistent with applying this principle you can't conclude anything at all. If you see the Sun and planets move every day, would you eventually accept orbital mechanics, or would you prefer the explanation that "orbital mechanics is false, everything actually moves however it wants according to random unknown factors, but those factors were arranged just so that whenever we make observations, standard orbital mechanics appears to be true"?

Suppose we're betting on horce races, but I win 100 times in a row while you always lose. Would you accept my explanation that "this was merely superdetermined to be the case"? Or would you start to suspect that I'm stealing your money?

Superdeterminism is philosophically equivalent to Cartesian skepticism. It's just a minor twist on being a brain in a vat. Scientists reject this not because we can disprove it, but because you can't do anything if it's true. I mean, you might as well not bother getting out of bed in the morning.

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