How can a magnet be explained based on quantum properties? This seems like an obvious thing, but I can't find it online. The best I can do on my own is that systems are at lower energy when the spins are aligned, so that's why magnets attract one another. The spin transfers angular momentum to remote charged particles, causing them to move in curved paths. But that's not right: there isn't any transfer because the angular momentum of the original particles remains unaffected. Or something like that.