Double Slit Experiment

How does science work? And what's all this about quantum mechanics?

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rmuszynski
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Re: Double Slit Experiment

Post by rmuszynski » Thu Dec 13, 2018 3:43 am

Thanks Atla and arising_uk for replies and I have seen the oil drop video before, thanks arising_uk.

Atla said "Your idea seems to be similar to the idea in the opening post in this topic. But the individually fired particles don't seem to interact with each other at all. You could fire just one particle no more, and it will still arrive at a position consistent with a wave pattern".

Yes, Atla in my explanation the particles do not interact with each other, at least not directly. That is correct. They only interact with (and are guided by) the waves generated by previous particles. They can only be said to interact with each other very indirectly via the waves they form. One particle on it's own as the initial particle would not give the pattern. It would only create the first wave that any subsequent particles' waves could interfere with. Once an initial wave pattern is created though, with some initializing particles shall we call them, you could, in theory, stop the main firing and then immediately fire just one particle through and it would add to the pattern seen at the screen provided it was fired 'in time sync' with the previous particles. What I mean is It would have to be fired with the same time interval that the previous particles had between them. That would be true of either the simultaneous or alternate slit cases or destructive interference would occur. In the alternate case all that then happens is that a given particle is interacting with a slit half as often as would be the case with simultaneous firing through both at the same time, However, half the frequency means the wave created are still in sync (I think) as would firing at twice the speed, etc.

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Noax
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Re: Double Slit Experiment

Post by Noax » Thu Dec 13, 2018 9:30 pm

rmuszynski wrote:
Thu Dec 13, 2018 3:43 am
Yes, Atla in my explanation the particles do not interact with each other, at least not directly. That is correct. They only interact with (and are guided by) the waves generated by previous particles. They can only be said to interact with each other very indirectly via the waves they form. One particle on it's own as the initial particle would not give the pattern. It would only create the first wave that any subsequent particles' waves could interfere with. Once an initial wave pattern is created though, with some initializing particles shall we call them, you could, in theory, stop the main firing and then immediately fire just one particle through and it would add to the pattern seen at the screen provided it was fired 'in time sync' with the previous particles. What I mean is It would have to be fired with the same time interval that the previous particles had between them. That would be true of either the simultaneous or alternate slit cases or destructive interference would occur.
This idea is easily falsified by running each particle through similarly dimensioned slits in 1000 different labs across the world, each doing one particle each, all at the same time, or weeks apart if you like. By your assertion, no pattern should form when the results are combined. By QM prediction (never mind which interpretation), the interference pattern will form.

rmuszynski
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Re: Double Slit Experiment

Post by rmuszynski » Thu Dec 13, 2018 11:51 pm

Thanks for the response Noax. I like that combined lab result experiment of yours. It would indeed falsify mine if any QM effect meant that each of your separate single particle firing experiments caused the particle to land at a position on the screen based on just a 'statistical probability' of where it should land rather than necessarily going straight on and in combination then giving an interference pattern. Please remember though that my interpretation is a totally deterministic non QM one where the first particle will always go straight on because there is nothing to interfere with yet.

I believe it is actually possible to fire individual electrons, photons (and molecules?) nowadays with special equip. so your experiment could (in principle at least) be done in say 10 or 100 labs to be practical and to see if there was even a tendency for the pattern to emerge. Any pattern seen after combining the results might not be very distinct initially due to not enough total firings but any significant number of the dots deviating from the straight though case might be enough to imply the emergence of an interference pattern. They could of course just repeat the experiment in each lab by firing another single particle after whatever is though to be enough of a time span and adding it to the combined pool of results so far and then repeat if necessary to confirm any pattern.

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Noax
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Re: Double Slit Experiment

Post by Noax » Sat Dec 15, 2018 4:53 pm

rmuszynski wrote:
Thu Dec 13, 2018 11:51 pm
Please remember though that my interpretation is a totally deterministic non QM one where the first particle will always go straight on because there is nothing to interfere with yet.
Well that throws it out the window right away. If you predict the first particle always goes straight, you only need one test to falsify it. Draw an X where it is supposed to land and fire one shot. It will very likely miss the X, but not definitely. If it happens to hit it by freak chance, do it a 2nd time in some other lab setup.
I believe it is actually possible to fire individual electrons, photons (and molecules?) nowadays with special equip. so your experiment could (in principle at least) be done in say 10 or 100 labs to be practical and to see if there was even a tendency for the pattern to emerge.
I think 100 dots is plenty to show such a pattern. 10? Probably not.

rmuszynski
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Re: Double Slit Experiment

Post by rmuszynski » Sat Dec 15, 2018 5:24 pm

With due respect and thank you very much again for responding noax, I must defend my position and beg to differ with you. I work at Dundee University and have spoken to Dr Colin Campbell there. He is looking at it with me soon in terms of my thoughts. His department leader said to me "I wish you luck with that one" with what I could take as a bit of as sarcasm, although I've tried not to be too disheartened by that. The whole reason I'm doing anything with it is precisely because if greater minds than mine cannot agree then maybe it's because there is a simpler explanation under their nose they haven't thought of and my humble attempt is just a try to find one. I doubt they have the equipment to test with individual particles but they may well be connected with establishments that do. My basic take on it is that like skipping stones on water, the waves, if they exist, may travel much slower but having a longer duration (and therefore possibly influence on the system) than the particles.

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Noax
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Re: Double Slit Experiment

Post by Noax » Sat Dec 15, 2018 6:00 pm

Noax wrote:
Sat Dec 15, 2018 4:53 pm
I think 100 dots is plenty to show such a pattern. 10? Probably not.
The wiki page on the double slit experiment actually has output of about 10, 100, 1000, maybe 2000 and 4000 from the looks of it.
The 100 plot is not enough. 500 should do I think.

You could probably do it with one lab, but change the setup each time, moving it to a different location, using a different (but identical) cards with slits, and by 'erasing' each prior run by sending different things (photons of different wavelength say) through, but not keeping the data from those alternate runs.

You seem to be in a unique position to actually try some of your ideas. Go for it!
Devices that fire single electrons or photons have been around for many decades. They're not that exotic. I hope your university has something that can serve the purpose.

rmuszynski
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Re: Double Slit Experiment

Post by rmuszynski » Sun Dec 16, 2018 12:02 am

OK, yes, I will ask them if they can get it done and with your methodology in mind regarding our discussions on single firing experiments but that will be after xmas now of course. I also need to run the basic idea past them properly though as haven't done that yet.
On that note 'Merry Christmas' to all on the forum and esp you noax for recent inputs.

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bahman
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Re: Double Slit Experiment

Post by bahman » Tue Dec 25, 2018 8:07 pm

philosopher wrote:
Wed Nov 28, 2018 4:49 pm
I'm really fascinated by the double slit experiment. Turns out that if you fire particles - electrons or even molecules at double slits, one at a time, and wait 1 sec. or more before you fire the next particle, after some time it will create an interference pattern on the screen.

How can individual particles not yet fired somehow "know" where to land according to the particles already fired, and create the overall picture of an interference pattern?

I mean, it seems like they are communicating with each other - particles fired "tells" other particles yet to be fired, where to land...

Is this evidence of the so-called entanglement? I mean, usually entanglement is understood as that if two particles once close to one another, becoming separated they remain entangled with their spin.

But doesn't the double slit experiment prove that all particles in the entire universe are somehow linked/entangled since the big bang?

Maybe there is a universal wave, instead of individual particles being interpreted as waves, maybe everything in the entire universe is one gigantic wave of real particles entangled?

Or am I talking gibberish?

What did I get wrong and more importantly, how did I get this wrong?
I guess so. You just need to show that you can produce the interference pattern using entanglement.

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