Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Feynmann's electron double slit experiment

  1. Jan 5, 2012 #1
    Hi, I was trying to learn a bit of quantum mechanics from Feynmann lectures. In the 3rd volume of the Feynmann lectures, he talks of the double slit experiment with electrons. He says that if we keep a light source near the first slit, so that every time an electron passes it scatters light and lets us know that it has passed, if the wave length of the light is small enough we will not get the interference pattern. My question is, what if we remove the light source and keep another kind of a detector, something that detects the electrons field, will we still get an interference pattern?
    More over is the destruction of the pattern related to the collision with photons or is it due to the very act of observation that lets the observer know which hole the electron went through?
     
  2. jcsd
  3. Jan 7, 2012 #2

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    The electric field is mediated by photons (light) so it would still be a light source ... any other way of detecting the electron which is good enough to tell us which slit it went through will destroy the diffraction pattern.
    Anything capable of telling us the position of the electron will also give the electron a random kick - the more accurately we can tell the position, the bigger the kick - so the answer to your question is: the interaction ... we know which slit the electron came through because of the interaction, the ineraction causes both out knowledge and the changing of the pattern

    Feynmans lectures on wave-particle duality are on youtube - he explains them much better in person than in the bound undergrad lectures.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Feynmann's electron double slit experiment
Loading...