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

Uncertainty principle and double slit

  1. Sep 21, 2015 #1
    sir, what if we use Heisenberg's uncertainty principle to explain double slit experiment?
    i was reading about uncertainty principle for last few days n i was reading about double slit experiment and i realize that we can explain why we get electrons everywhere on the screen (getting interference i think can be explained using wave function or something similar to it which will be a mathematical model) rather then getting 2 bands... as we are using narrow slits we can find position of electron wid accuracy which results in uncertainty in momentum..as width of the of the slit is narrow bt nt height which implies uncertainty in momentum in the direction the width increases.
  2. jcsd
  3. Sep 21, 2015 #2


    User Avatar

    Staff: Mentor

    That works as a heuristic explanation for diffraction (the beam spreads out after the slit, and the narrower the slit the greater the spread) but not for interference (dark and light bands appear in the region of overlap when there are two slits).

    However, diffraction and interference can be calculated directly from the wave function without appealing to the uncertainty principle, so that may be a better starting point for the explanation of both phenomena.
  4. Sep 21, 2015 #3
    An interesting question. In a similar way to how confinement in a well leads to quantisation, does confinement in space in slots perpendicular to the beam lead to the quantisation of the momentum in the perpendicular direction?
  5. Sep 21, 2015 #4


    Staff: Mentor

    By itself it cant explain it.

    I personally don't like the usual wave-particle explanation because as you progress in QM you find its basically a myth:

    A much better explanation (still not perfect though - even it has issues) combines the uncertainty principle and superposition principle in a very elegant way:

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook