- #1
Malamala
- 299
- 27
Hello! Assuming we have a 2 level system interacting with an EM field in the RWA and dipole approximation, we would have in the basis of the 2 unperturbed atomic states a 2x2 Hamiltonian matrix with off-diagonal terms. By diagonalizing this Hamiltonian we obtain dressed states which are the eigenstates of the atom-EM field interacting system and are shifted by a given amount relative to the unperturbed levels. Mathematically it makes sense and it is straightforward, but I am not sure what is happening physically, especially in the case of far detuning. On resonance for example, the atom undergoes Rabi oscillations and there is a clear interaction with the EM field, but in the far detuned region, how does the atom knows about the existence of the EM? Is it simply because there is a very small probability (small Rabi frequency) of Rabi oscillations due to the fact that the transition between the 2 levels has a line width and even if the laser frequency is far detuned it will still excite the transition once in a while? Or is there some other mechanism by which the atom feels the EM field?