Half a croissant, on a plate, with a sign in front of it saying '50c'
h a l f b a k e r y
No serviceable parts inside.

idea: add, search, annotate, link, view, overview, recent, by name, random

meta: news, help, about, links, report a problem

account: browse anonymously, or get an account and write.



Double Slit Feedback Loop

Double Slit Experiement feedback goes loopy
  [vote for,

The well known double slit experiment set up with electron detectors on its slits which will detect the moment an electron passes but will never divulge the information on pain of death, (or to be precise would blow up and destroy the experiment, rather than pass the information on. )

With one exception: if an interference pattern appears on the collection screen, ( implying wave manifestation) the slit detectors would be electronically unlocked by this outcome. (How is the interference pattern detected? It shouldn’t be too complicated. Maybe something like a bar-code reader, or simple pattern recognition programme does it and then sends an ‘unlocking signal’ to the slit detector.)

Then the slit detector would immediately stop being a secretive detector, and allow the information about when and which slit the electron went through to be passed on to the scientist.

In other words, the detector is useless unless the electron acts as a wave, but if the electron acts as a wave, the detector is no longer useless, so the electron cannot act as a wave, it must be a particle, but that would make the detector useless, so the electron must act as a wave, but if it’s a wave the detector is no longer useless and ..blah blah blah.. to eternity.

I’m new to thinking about this stuff, and I tried to see if this kind of thing had already been done, but am none the wiser for looking into it. Very hard to follow some of the ideas. Plus maths for me a no- no. So I put it to anyone who grasps this stuff better. Does anyone know A) is this baked? B) what would it look like? Would electron toggle rapidly between wave and particle, or something else happen? C) is it the same as a computer dealing with ‘ this statement is a lie’? Like the incompleteness theorem

DDRopDeadly, Nov 22 2017

oil droplet walkers on silicon; pilot wave theory https://www.youtube...watch?v=WIyTZDHuarQ
[beanangel, Nov 22 2017]


       This is a cool thought experiment. I think (and I don't know the details well enough to be sure) that it's basically equivalent to the "delayed choice" experiment. I'm not sure how that one fails, but basically nature bites you in the arse and you end up no wiser.
MaxwellBuchanan, Nov 22 2017

       I'm pretty sure they most often use photographic film to record the impact of photons that pass through the double-slit. When electrons or other particles are employed instead of photons, they probably have some other type of chemically treated strip that reacts to impacting particles.   

       I do know that the experiment often involves just one particle at a time passing through the double-slit (and indeed still gradually builds up an interference pattern).   

       I speculate that the simplest explanation for the interference pattern involves the virtual particles in the vacuum. Any real particle moving along is constantly interacting with those virtual particles. The momentum of the real particle is uncertain, meaning that some fraction of it is always getting carried by nearby virtual particles. It is easy to imagine the total momentum as being at least partly a wave across a sea of virtual particles.   

       *Usually* there is no net effect, because virtual particles must vanish and real particles always get their momentum back. However, when the real particle encounters a double-slit, some of its momentum can be carried by virtual particles through the slit that the real particle does not pass through. The real particle still gets its momentum back, but now the slits have imposed an effect upon the wave-front of the distributed momentum (distributed per the Uncertainty Principle) that passed through the double-slit.
Vernon, Nov 22 2017

       [vernon], [DDRD] is talking about the detectors at the slits, which record the passing-by of an electron; not the detector at the screen.
MaxwellBuchanan, Nov 22 2017

       The screen (of film or equivalent) is a detector, the thing that that detects the interference pattern. The simplest explanation for the destruction of that pattern when trying to detect the particles generating that pattern is:   

       1. an interaction with that particle must be accomplished.
2. any interaction changes the momentum of the particle.
3. If the particle reaches the detector/screen at all, it will now reach it in a different place than it would have reached, without the intermediary interaction.
Vernon, Nov 22 2017

       Yes, but in [DDRD]s experiment, the screen is of secondary importance (ie, it can be film, photomultipliers, or whatever). The key element is the detectors sitting next to each of the two slits.   

       Also, your 3-step explanation is still grounded in classical concepts, whereas I think that the two-slit experiment has been shown not to be tractable to any classical theory. Quantum mechanics is just other.   

       For instance, a particle does not reach any part of the screen - it is simply detected at one location of the screen, which is a very different kettle of geese.
MaxwellBuchanan, Nov 22 2017

       The experiment described in the main text here requires the self-interfering wave-form to be detected. This is theoretically possible at any point *after* the particle has exited the double-slit, but impossible on the other side, since the wave is not self-interfering before the particle reaches the double-slit.   

       What I wrote in my previous anno (especially #2) is entirely acceptable to QM --one of the foundations of QM, the Uncertainty Principle, directly derives from how observations affect the things observed.   

       And so, by attempting to observe how a particle's waviness self-interferes, that attempt destroys the ability of the particle's waviness to self-interfere.
Vernon, Nov 22 2017

       Indeed it does, which is rather the nub of [DDRD]'s idea.
MaxwellBuchanan, Nov 22 2017

       No in fact your idea MB. Upon reading your Shodingers Twin Slits expt from 2007.. already baked by you. Ps your title is also more erotic, damn
DDRopDeadly, Nov 22 2017

       Anything with twin slits in it is bound to have a little frisson.
MaxwellBuchanan, Nov 22 2017

       Wait!! Someone read one of my ideas???
MaxwellBuchanan, Nov 22 2017

       I misread the title and thought the idea was going to be about a twin bowled toilet.
xenzag, Nov 22 2017

       [Vernon]'s annotation reminded me of a simulated double slit experiment where drops of oil diffract at a double slit. They mention pilot waves at the video. [link]
beanangel, Nov 22 2017

       I think the "pilot wave" concept got discredited and its formalization sort of morphed into mainstream QM.
MaxwellBuchanan, Nov 22 2017

       Reading this I almost had an idea about using a double-slit experiment to perform otherwise impossible calculations. I was right on the tip of my brain, which started to smoke and bubble before the idea slipped away. Now I'm 15 IQ points down and have no idea where I was going with that. -_-
Voice, Nov 29 2017


back: main index

business  computer  culture  fashion  food  halfbakery  home  other  product  public  science  sport  vehicle