Recent content by Lucas-

So if I understand correctly, we find a new basis in which the perturbation is diagonal and when we want a specific ket we can write it in this new basis and we'll get the energy shift we want when we turn on the perturbation ?

Hello, In the case of Stark effect for example, one may find the correction for the |1s> state easily by applying non degenerated perturbation theory. However in the degenerated case it's seems as though we can only treat the whole n=2 level for example and not individual eigen states. That, I...