How can an electron pass through two slits at once and interfere with itself?



How can an electron pass through two slits at once and interfere with itself?

In: Physics

Because it has some wave-like properties. The double-slit experiment, which used photons instead of electrons, was *the* experiment to prove “wave-particle duality”, the fact that elementary particles are something that behaves like both a wave and a particle.

A particle obviously can only go through one slit at a time. A wave can obviously go through both (just imagine a single wave on the ocean hitting a seawall with two gaps in it). In the latter case, you’ll get a “piece” of wave coming out of each gap and those two pieces can happily interfere with each other. Electrons are like photons, they have some wave-like and some particle-like properties.

The whole “interferes with itself” thing is the electron showing off it’s wave-like stuff.

Tl;dr : I don’t really know.

**(this is how I try to make sense of it. might be complete bs):** Since we can’t really know what an electron looks like (we don’t…right?) we just look at it’s individual properties. The earliest properties we saw matched those of particles, so we thought it must be a particle. Then some other properties matched with those of waves. So some people said it must be a wave. Then people started arguing about what it was (and ended up making really cool theories explaining lots of weird phenomena with both, particle nature and wave nature). In the end, they just decided that it is neither a particle nor a wave. I actually think it’s misleading when some books say that electron is both a particle and a wave. Because it’s neither. It just has some properties in common with both of them.

It’s like how you might have some qualities in common with a really tall guy, and have some other qualities in common with really short guy.

* One experiment showed that you can reach the upper shelf, like the tall guy and unlike the short guy. So they assumed you must be a tall guy.
* Another experiment showed that you did not get selected into the basketball team, like the short guy, unlike the tall guy. So they assumed you must be a short guy.

So, which one are you? Well neither. And if someone can only understand people in terms of “tall” and “short”, he/she is going to be very confused because in everyday life you’d seem to be changing properties, sometimes acting like tall guy, sometimes acting like short guy.

I know I know, it sounds like all I’m saying is that “that’s how it is, deal with it”. But I’m not. Honestly, I don’t understand it all myself. I think Feynman explained how we try to explain things in terms of things we already know. But it’s impossible to paint a correct picture of an atom in terms of anything else, since it’s like nothing you’ve ever seen before. So saying it’s like a particle or a wave is not exactly correct.

**Once again, it’s how I tried to make sense of it inside my head. I’m just some guy sitting in his PJs. So feel free to correct me if something’s wrong here.**