  The phenomenological two-level atom is re-analysed using the methods of
effective field theory. By presenting the Dicke-Jaynes-Cummings model in real
space, an exact diagonalization is accomplished going beyond the rotating wave
approximation. The meaning of the symmetries and conserved quantities in the
theory is discussed and the model is related to non-equilibrium field theory.
The structure of the solution raises a question about the rotating wave
approximation in quantum mechanics.
