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Gravity and the double slit experiment

  1. Apr 28, 2013 #1
    How would the double slit experiment work if we were to use gravity as a detector? That is, a very localized but massive gravitational field near one of the slits. Since we are not observing when an electron passes through the slit, the interference pattern should remain.

    But on the detector screen the electron would arrive a bit later if it came from the slit nearest our miniature gravity field.
     
  2. jcsd
  3. Apr 28, 2013 #2

    mfb

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    If the gravitational interaction is strong enough, it can be an observation.
    If that delay is longer than the coherence length, you lose interference.
     
  4. Apr 28, 2013 #3
    Firstly this cant work as we can't just 'çut off' gravity between one slit and the other (provided they are close by).
    Secondly, relativistic effects would kick in and we would be left with electrons going through the slits with different weights. Hence the pattern would be the close field one. (ie 2 shadows)- maybe I've simplified this too much, ill have to do the math on it.
     
  5. Apr 28, 2013 #4
    But otherwise a very interesting thought.
     
  6. Apr 29, 2013 #5
    well, i just a beginner in Quantum Physics, but i would like to know why would there be any kind of deflection in interference pattern. i believe gravitational field SHOULD NOT any cause any kind of indifference. if yes, i would like to know how and why?
     
  7. Apr 29, 2013 #6

    mfb

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    Gravitational interaction is not special here - you would need some ultra-dense object close to one slit to see any difference, so the experiment is purely hypothetical, but the setup is similar to a different electric potential at one slit.
     
  8. Apr 29, 2013 #7

    DrChinese

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    An issue is:can gravity serve as an interaction which causes collapse? There are certainly arguments for both sides of that proposition. If gravity is not a quantum force, you might guess the answer is NO.
     
  9. Apr 29, 2013 #8

    mfb

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    Neutrons, bouncing above a surface due to gravity, show quantized energy states.http://www.nature.com/nphys/journal/v7/n6/full/nphys1970.html [2] Gravity and quantum mechanics work together, and you don't need more (well, apart from that ultra-dense object with a very well-defined momentum) to destroy interference.
     
    Last edited by a moderator: May 6, 2017
  10. Apr 29, 2013 #9

    DevilsAvocado

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    Electrons in the double slit seem very popular lately, but if we use photons instead, we don’t need to hire the LHC to create a Micro Black Hole. :smile:

    Just prepare one slit with a Bose–Einstein condensate and run Slow light thru the slit, and the effect would be equivalent:

    https://www.youtube.com/watch?v=EK6HxdUQm5s


    = no interference
     
    Last edited by a moderator: Sep 25, 2014
  11. Apr 29, 2013 #10

    DrChinese

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    Nice references, very interesting (and clever) stuff.
     
    Last edited by a moderator: May 6, 2017
  12. Apr 29, 2013 #11

    DrChinese

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    And as always, Devil has those cool visuals... :smile:
     
  13. Apr 29, 2013 #12

    DevilsAvocado

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    Thanks DrC, but you know me... sometimes there’s more ‘flashing’ going on... than actual entangled neurons producing something coherent in the avocado brain... :rolleyes:
     
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