Double Slit Experiment No Mystery • Hacker News Board

Re: Double Slit Experiment No Mystery

#81

Post by lonelappde » Sat, Oct 26, 2019, 6:07 PM UTC

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…

HN has never had any particular quality or accuracy filter for content, and people rarely click through links before voting.

Re: Double Slit Experiment No Mystery

#82

Post by justinmchase » Sat, Oct 26, 2019, 6:15 PM UTC

mikhailfranco wrote: post #54

QM is easy to describe. There is wave-particle duality, but not at the same 'time' , only in a strict alternating sequence of propagations and interactions. Propagation is completely wave-like. It is unitary and time reversible, without loss of information. There is no particle there, and no 'there' there, as the propagation is non-local. Waves have complex amplitudes. Interference happens because that's what waves d…

> QM is easy to describe.

That's easy for you to say!

Re: Double Slit Experiment No Mystery

#83

Post by ksaj » Sat, Oct 26, 2019, 6:20 PM UTC

Has the double slit experiment been done and verified in a vacuum? I'm able to produce the superficial results with a simple neon laser, but it always struck me that outside a vacuum, there is a lot available to skew those results.

Re: Double Slit Experiment No Mystery

#84

Post by hcarvalhoalves » Sat, Oct 26, 2019, 6:22 PM UTC

scotty79 wrote: post #73

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 bu…

So, Newtonian physics is an approximation for certain wave shapes/magnitudes?

Re: Double Slit Experiment No Mystery

#85

Post by scottlocklin » Sat, Oct 26, 2019, 6:25 PM UTC

> What many don’t realize is that the double slit experiment (with particles), proposed by Feynman in 1963, was for decades only a thought experiment. Finally, in 2013, it was successfully performed with electrons. It’s easy to see why it took so long: the slits were 62 billionths of a meter apart.

Who is this clown? I did the two slit experiment using a CRT (aka using electrons) in undergrad experimental physics class in the late 80s, and unless I had some amazing experience, I'm pretty sure every undergraduate physics major does the same thing. The '37 Nobel in physics was awarded more or less for doing this in the 1920s after de Broglie said it would be there.

Re: Double Slit Experiment No Mystery

#86

Post by simonh » Sat, Oct 26, 2019, 6:34 PM UTC

Koshkin wrote: post #78

simonh wrote: post #36

Earlier quoted context omitted.

Is there anything about the point being made that is inconsistent with that?

A theory without observables is not science.

The point being made is that all observations change the thing being observed, so you have to be very careful what you measure and how you measure it. That is all. This is a basic point in science that is often missed. As here, apparently.

Re: Double Slit Experiment No Mystery

#87

Post by jl2718 » Sat, Oct 26, 2019, 6:42 PM UTC

Reading things like this article and replies, it seems apparent that physics research, or at least teaching, often blurs the distinction between experiments in thought or otherwise explaining a theory, and those that motivated theory by empirically disproving previously-held beliefs.

Also I’ve noticed a strange form of entropy in physics that tends to show more evidence for models that have the largest number of equivalent formulations based on different assumptions. You could say that this is a result of how physicists work to prove their own theories, but perhaps the gods work the same way.

Waves of probability amplitudes with quantized action is a nice abstraction that works so far, but so was continuum mechanics. Wave-like observations could easily be a simple consequence of the central limit theorem in the same way.

Re: Double Slit Experiment No Mystery

#88

Post by Balgair » Sat, Oct 26, 2019, 6:43 PM UTC

scottlocklin wrote: post #85

> What many don’t realize is that the double slit experiment (with particles), proposed by Feynman in 1963, was for decades only a thought experiment. Finally, in 2013, it was successfully performed with electrons. It’s easy to see why it took so long: the slits were 62 billionths of a meter apart. Who is this clown? I did the two slit experiment using a CRT (aka using electrons) in undergrad experimental physics cla…

Seriously! We literally did it in our modern physics lab. For me that was ~2004. It's not a terrible difficult experiment to do at home. Also, 62nm is not a particularly small distance in electro-optics. You can buy polarizers and the like off Thorlabs for ~$9.

This person seems to be a bit of a crank.

Re: Double Slit Experiment No Mystery

#89

Post by scottlocklin » Sat, Oct 26, 2019, 7:01 PM UTC

scotty79 wrote: post #73

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 bu…

If you have wave-systems with high enough fidelity (Q-factor in a cavity for example), they behave a lot like particles in certain energy/time regimes. People yelling from a mountain top hear echoes.

Re: Double Slit Experiment No Mystery

#90

Post by ddalex » Sat, Oct 26, 2019, 7:02 PM UTC

aeternum wrote: post #77

dekhn wrote: post #26

Earlier quoted context omitted.

+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).

but how do you get the sine curve in the first place? because you're not subtracting a sine curve, you're subtracting non-coincidences, for which there is no reason they would be on the sine curve