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Double Slit Experiment No Mystery

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Re: Double Slit Experiment No Mystery

#71

Post by jeremysalwen »

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…

Superdeterminism is the physics equivalent of saying the fossil record was placed there by the devil to deceive us into believing evolution.

Re: Double Slit Experiment No Mystery

#73

Post by scotty79 »

Duane doesn't explain double slit experiment. It says momentum exchnge is quantized if you direct particle at lattice and this gives same pattern as interference.

If you consider single electron in this interpretation, point like particle without any associated wave or ability to be in more than one point of space at the same time ... when it is directed and passes through one of the slits, it produces the pattern but only if the it potentially could have been directed at the other slit.

How the hell what could happen with a particle (but didn't) could influence what actually happened to the particle (quantized, not normal momentum exchange)?

--

For me the way to deal with weirdness of double slit experiment is that electrons and such are just waves, all the time. Fuzzier, sharper but always waves. The only thing that makes us think that's not the case is that, when they exchange energy and momentum, it's governed with same equations as if they were two balls bouncing off of each other.

The truth in my opinion is that electrons don't bounce like tiny balls, but balls exchange energy and momentum as if they were huge, very sharp electrons. Macroscopic balls are waves too, but imperceptibly because they are build out of bazzilion particle waves all tangled together into a very constraining packet.

Re: Double Slit Experiment No Mystery

#74

Post by lordnacho »

quattrofan wrote: post #11
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…

How can a "thought experiment" demonstrate anything?

Common example is dropping two balls of different mass connected by a chain off a tower.

The point is not that is demonstrates something empirically, which of course it doesn't. But it does say something about which hypotheses make sense within whatever assumptions you're making.

Re: Double Slit Experiment No Mystery

#75

Post by robocat »

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…

> allows you to detect the path AFTER the photon has traveled through

It is NOT AFTER: "Why delayed choice experiments do Not imply retrocausality"

https://link.springer.com/content/pdf/10.1007%2Fs40509-014-0...

tl;dr: the detector collapses the state, detection does not mean both paths were not "taken". This is the same as detecting a photon on a screen after a double slit.

Disclaimer: I only skim QM stuff, I am not a physicist

Question: what's the name for this experiment where light is interfering with a "slower" beam of itself (legend: ⫽ are beam splitters, \ and / are mirrors, arrows are photon):

  → ⫽ → ⫽ → detector

    ↓   ↑

    \ → /

Re: Double Slit Experiment No Mystery

#76

Post by [deleted] »

ryanthedev wrote: post #61
coldtea wrote: post #43

Earlier quoted context omitted.

> 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.

[deleted]

Re: Double Slit Experiment No Mystery

#77

Post by aeternum »

dekhn wrote: post #26
fsh wrote: post #19

It is very common in physics that the same phenomenon can be explained using different concepts. Treating particles hitting a regular structure as diffraction of de Broglie waves gives exactly the same results as the momentum transfer approach the author prefers. In fact, both can be derived from standard quantum mechanics and both are widely used, depending on which is easier in the particular case. However, scatter…

+1 for the delayed choice quantum eraser as being the one experiment that makes it more or less impossible to argue against quantum weirdness.

The delayed choice quantum eraser is often explained as being more 'spooky' than it actually is.

The interference patterns only appear when you compare coincidences between the detectors. It's easy to see you could get an interference pattern after the fact by taking a bell curve (no interference) and subtracting out a sine curve (interference).

Re: Double Slit Experiment No Mystery

#79

Post by nobodyandproud »

missosoup wrote: post #34
headmelted wrote: post #6

This misses whole swathes of the double slit experiment. It doesn't cover the Observer problem, which means it doesn't acknowledge duality, which (you would have to assume) means it doesn't even recognise delayed-choice quantum erasers. At the risk of getting downvoted to oblivion I feel like the author needs to study up on quite a bit more of this research as there's a much larger body of evidence than that which is…

The author of TFA has little understanding of what they're talking about and misses all of the nuance of the double slit experiment and its relationship to other QM phenomena like the Dirac three polarizer experiment[1] and delayed choice quantum eraser experiment[2]. The three polariser experiment in particular makes it almost impossible to argue that light is a particle even if it had hidden state, unless that hidd…

The collapse of observing entangled particles can be non-local and isn’t controversial.

So why would hidden state matter? In fact, Bell’s Theorem allows this.

Re: Double Slit Experiment No Mystery

#80

Post by tus88 »

The problem I have with this. Quantization must be a factor of wavelength and perhaps width of one slit. Yet the interference pattern produced by the double slit experiment depends on the distance between two slits. Diffraction pattern is not the same as an interference pattern, something the original researchers were well aware of.
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