With reference to an electron when radiating a quantum of energy (photon). QM provides the probability wavefunction as a superposition between states and seems to be telling us that it cannot actually exist 'in between' states, but is instantaneously interfering between them. How does the electron change from the excited state to a stationary state without ever existing in between them. Also, does the electron wavelength change. Any help welcome.
>Need QED, not just QM. Yes, its actually QED that gives this analysis. Is this all we can currently determine about the electron during transition between states- That is, only a probability of where it can be found.
I think there is a simple way of looking at this, it is a bit of a mix between the particle and wave view of matter but it works quite nicely. Assume that we start with a hydrogen atom. The electron in the ground state is is buzzing around in ths s-orbital. Now, remember that the s-orbital is an eigenstate of the undisturbed hydrogen atom so this is the way the probability of position and angular momentum is distributed initialy. If now an electromagnetic wave passes by, the electron will feel the electric field and move according to the field. The instantaneous eigenstate is different than the s-orbital and is usually described as a mixture if other states but it is essentially a mathematical trick to calculate it's motion ands position. When the disturbance goes away, the electron might be in a position and momentum corresponding to another eigenstate of the undisturbed atom which means that it has been excited. So the actual process of excitation takes a couple of wavecycles. The probelm is that the actual measurement of electron state can only give us either one state or another but that liees more in the quantum mechanical measurement process than the electron state. This is ofen mixed up so some people claim that the quantum-leap is instantaneous.
