DECOHERENCE FROM SPONTANEOUS EMISSION

Starting from a generalization of the Weisskopf-Wigner model for the c ase of a two-level atom with a largely spread center-of-mass wave func tion, we show that spatial correlations are destroyed to some extent b y a spontaneously emitted photon. We derive a particularly simple form of the corresponding decoherence function and determine the dependenc e of the decoherence on orientation and size of a detector registering the outgoing photon.