RESONANCE FLUORESCENCE OF A 2-LEVEL ATOM EXCITED BY A SUPERPOSITION OF COHERENT STATES, AND THE INSTABILITY OF THE AVERAGE ATOMIC DIPOLE-MOMENT

We find the evolution of average atomic variables in the resonance flu orescence of a two-level atom excited by a superposition of coherent s tates shifted in phase by pi. A new effect is predicted, the quantum i nstability of the average atomic dipole moment, with a strong correlat ion between atom and field being the reason. We propose different ways of verifying the effect in experiments involving high-e optical and m icrowave cavities. (C) 1997 American Institute of Physics.