Modern Physics for Engineers Lecture slides 07c – Young’s slits and quantum mechanics

This lecture part discusses a classic conundrum in quantum mechanics that is illustrated by Young's slits. Electrons do diffract as expected by Young's slits to give an interference pattern, but we apparently cannot "know" which slit the electron went through. In quantum mechanics, in one view that question is meaningless; indeed if we do measure that, we lose the interference pattern. (slides)