Hello everyone. Can someone explains me the meaning of quantum state transition? For example consider an electron which is in the superposition of two energy eigenstates of a given hamiltonian, now, if no one perturbs the state with a measure, nothing happens and the superposition remains the same for all the time. Suppose you had been able to measure one of the states, this means that the electron decays in that state and it remains there if no perturbation is applied on the system and you have all the probability on that state, am I right? If so, I think this is described by the fact that the two states are orthogonal. Consider the case where the wave function is a dirac delta in 0 with the hamiltonian of the free particle, what happens theorically after you made the measure of the position? The state remains the same or it evolves spontaneously?