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    Thread: Double-slit detector

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      Double-slit detector

      Does anyone know or have an interest in finding out how exactly physicists detect if a particle goes through one slit or the other in the double-slit experiment? Every book and article I read seems to elude this part.

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      That's something I'm curious about as well. At one point I started a thread (in the wrong forum I think) about it, but learned very quickly that my understanding of the technology used was completely wrong. I assumed they used an electron microscope, which I reasoned would be like observing a pool ball by shooting a stream of pool balls at it. Apparently they don't use an electron microscope. Somebody directed me to a massive Wiki page listing dozens if not hundreds of different technologies that can be used to observe such particles, but I have no idea which one was actually used for that experiment.

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      The experiment is actually explained in detail in Brian Greenes the Elegant Universe and you would probably come to a better understanding of it by reading about it than watching a video.

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      Still didn't mention what type of device was used to make observations as the photons are going through the slits. That's what I'm interested in. If I get the book, will that be explained there?

      Cause what I can't understand is - how would it even be possible to "observe" photons in motion without disrupting them at the same time?

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      I've also seen that video. Very good basic explanation, but they just show this generic "camera" looking thing that the scientists used to make observations with. WTF is it??!!??

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      Wheeler's delayed choice experiment - Wikipedia, the free encyclopedia


      ^^^In this version it says they use a telescope... other than that it just says 'particle detector'. I'm not sure what type they meant. Sorry if that didn't help

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      Well thanks - I do appreciate the effort!

      A Telescope!!??

      I suppose if I really want to know in-depth info like this I need to get crackin' and read some books about it, huh?

      But the way they set that experiment up - so the observation takes place AFTER the photon has passed through the slit - does seem to remove the possibility that the observing device disturbs the behavior of the photons.

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      Xei
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      I believe that the mechanical interference doesn't actually matter as such, and stuff like the delayed choice experiment proved it. Basically with that experiment, even if you measure which slit the particle went through with some device, if you then irrevocably destroy the information, the interference pattern returns.

      Quote Originally Posted by Seroquel View Post
      That clip is from a bullshit religious propaganda film, so watch out.

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      Haha... if you ever find out for certain, let me know. I'm now curious, but not curious enough to read books on the subject. My 'to read' list is way too long already.

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      The implications are mind-boggling-



      ... What kind of crazy mixed-up world do we live in?!!??

      If I find out, I'll post here about it. I just can't believe any kind of camera could be used to record a photon, with any degree of magnification.
      Last edited by Darkmatters; 09-07-2011 at 01:51 AM.

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      Apparently the telescope version was more of a thought experiment to show that interference patterns are not affected by the 'short' distance between the slits and the detector screen.

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      Ok, that does make sense - a telescope allows you to get it far enough away.

      Mark my words - the ultimate finding of these experiments will be that subatomic particles actually float in the Aether....

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      The implications are mind boggling.

      But isn't that what cameras do? Record light? A photon doesn't seem much of a stretch from that. Maybe I'm missing something.

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      If it turns out they actually use cameras I'll bang my head on the wall!!!

      the whole reason I got obsessed with this in the first place is, I reasoned (assumed) that you can't see anything that small with anything short of an electron microscope. But I did see mention in that article you posted that what they're looking for is a "flash" in the slit. I suppose a camera could pick that up. In which case everyone can say derp to me and I'll be forced to ask "Why didn't somebody just explain that to me??!!!"

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      Quote Originally Posted by Xei View Post
      I believe that the mechanical interference doesn't actually matter as such, and stuff like the delayed choice experiment proved it. Basically with that experiment, even if you measure which slit the particle went through with some device, if you then irrevocably destroy the information, the interference pattern returns.
      Which makes what the information is actually made up of all the more interesting haha.

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      I'm really not sure if a camera can be used, don't quote me on it. But if it is just a matter of measuring light then it seems at least plausible to me. It definitely isn't a bad question but there is a big difference between 'seeing' something in the detailed scale of an electron microscope and simply 'detecting' something's presence.
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      Quote Originally Posted by Darkmatters View Post
      If it turns out they actually use cameras I'll bang my head on the wall!!!

      the whole reason I got obsessed with this in the first place is, I reasoned (assumed) that you can't see anything that small with anything short of an electron microscope. But I did see mention in that article you posted that what they're looking for is a "flash" in the slit. I suppose a camera could pick that up. In which case everyone can say derp to me and I'll be forced to ask "Why didn't somebody just explain that to me??!!!"
      That's interesting because if that's true then I can't see anyway a camera could pick up information from a particle that ends up at the screen unless it behaved like a wave lol
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      o.O

      well apparently when you measure things like this you 'get' the 'result' you're looking for in a sense.

      I really don't know what I'm talking about haha I'm just thinking it through now so hopefully I'm not messing things up for anyone. It is a cool experiment to read about.

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      I just can't help thinking that somebody will figure out one day that it was all a basic misunderstanding of the data and really it doesn't mean anything profound, and then physicists will have to say:


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      hahahaha

      Even if it was a misinterpretation of some sort it most likely still leads to some important discovery. But that would still be really funny.

      Scientific 'discoveries/facts' are proven wrong all the time.
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      I was replying to a reply that has now vanished o.O it made my browser very unhappy. Oh well.

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      sorry I had a thought that made me doubt what I said because it's hard to imagine Einstein's theory of gravitation being revolutionized into something completely different. Maybe his theory will be modified and built upon but will the bending of space and dilation of time ever be an outdated concept? Like science found out that the earth is round, I don't think that's gonna be outdated anytime soon lol.
      Last edited by Wayfaerer; 09-07-2011 at 03:38 AM.

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      Ahhh okay.

      No worries, it just made me do a reality check and I was sad to discover I wasn't dreaming

      hahaha

      I was basically going to agree with you that no scientific theory can be classified as right. I think we are more approaching (but not reaching) the limits of right with every new theory that is developed. But you have to classify the 'outdated' discoveries as wrong or inaccurate in order to move on to a more 'correct' understanding.

      To address a post that was never posted (maybe I just like to hear myself think)
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    25. #25
      Xei
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      Quote Originally Posted by Jenny5 View Post


      hahahaha

      Even if it was a misinterpretation of some sort it most likely still leads to some important discovery. But that would still be really funny.

      Scientific 'discoveries/facts' are proven wrong all the time.
      You can't 'prove wrong' models for existing data or qualified hypotheses. Science never asserts anything.

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