EMISSION FROM ATOMS IN LINEAR SUPERPOSITIONS OF CENTER-OF-MASS WAVE-PACKETS

We study theoretically the electromagnetic field emitted by atoms prepared in linear superpositions of several internal states, each of which is attached to a different center-of-mass wave packet by the preparation process. It is shown that the motion and mutual separation of the wave packets can be monitored either by observing the coherent spontaneous emission in a heterodyne experiment or by measuring the energy-absorption rate from a weak probe-laser beam. We also show that a three-level system involving three wave packets coherently emits photons, forming a linear superposition of states of opposite wave vectors. A heterodyne scheme for detecting the photons in this state is proposed.