Eric Weinstein

This says we did not understand classical electromagnetism until the late 1950s, well after Mr. Maxwell.

Now, what happened is we thought electromagnetism was that thing with the electromagnetic field components that we just saw.

If you put...

a wire coming out of the plane of the screen and you insulate it where it says solenoid.

Can we just isolate that?

Yeah, okay.

Now you have this crazy thing which is like you have a cathode ray tube at A, let's imagine, and you shoot it through a double slit

And you wanna know whether or not there's current flowing in this insulated thing that you can't see.

Now you think that the insulation is gonna keep you from being able to tell whether there's current flowing.

Turns out that the interference pattern

changes whether there's current even though there's no E and B fields outside of that insulated structure.

And that proves that it cannot be the electromagnetic field strength that actually determines electromagnetic phenomena.

What's really going on, can we call up the electromagnetic four potentials?

So one of the things is if you want to hang with the cool kids on any of this stuff, you don't try to map the electromagnetic fields because it's the electromagnetic four potential that's got it going on.

That was cool as fuck.

I'm looking for something that looks like A equals and then four components.

Well, hit that thing, what you just had.

That's good.

That A, where you see partial derivative of A, that thing is called the gauge potential.

And the gauge potential.