For explaining the double slit experiment, many such as Jim Al Khalili (https://www.youtube.com/watch?v=A9tKncAdlHQ) start with an example of having one slit - the pattern on the screen is that which you expect from particle-like behaviour. When there are two slits the probability waves of two electrons interfere to create an interference pattern arising from their wave-like behaviour. Since particle like behaviour when observed is still a wave, just concentrated at one point probabilistically, since the electron is unobserved, why does a single-slit experiment not also show wave-like behaviour and spread out (like light would)?
Asked
Active
Viewed 415 times
2 Answers
2
An electron beam passing through a single slit does spread out and forms diffraction patterns.
mike stone
- 58,971
- 4
- 53
- 158
1
Because the video is wrong, and it's a huge problem on YouTube videos even by reputable people. You need 2 overlapping (sum-of-squares) diffraction patterns (hint: wave) when you have which-way information. When you lack that information, an interference pattern (square-of-sums) modulates the overlapping diffraction patterns.
If the single pattern is an isolated stripe, opening the second slit will also produce an isolated stripe, not because there is no wave behavior, but because the wavelength is too short to observe it.
In an MIT video, they actually do the experiment:
JEB
- 42,131