303 | AMA | February 2025

2558.902 - 2582.643 Sean Carroll

In ordinary undergraduate quantum mechanics, if you have a hydrogen atom with its electron in the ground state and you ignore the rest of the world, then it will stay there forever, okay? It's a stable state. It's not going to do anything. It just sits there. If you excite it, so you send a photon in and you prod the electron to a higher energy state, the higher energy states are unstable.