QUANTUM-STATISTICAL ENHANCEMENT OF SPONTANEOUS EMISSION IN VELOCITY-SELECTIVE COHERENT POPULATION TRAPPING - MEAN-FIELD CALCULATIONS

We study the mean-field dynamics of atoms in a velocity-selective cohe rent population trapping (VSCPT) configuration, under the influence of resonant dipole-dipole interactions. By elimination of the transverse electromagnetic field we derive a Heisenberg master equation for an a rbitrary atomic operator. A closed equation of motion for the one-part icle density matrix can be given by employing a time-dependent Hartree -Fock (TDHF) factorization of the two-particle density matrix, thereby neglecting two-particle correlations, i.e., collisional effects. In t he case of bosons, the mean-field evolution mainly shows a quantum-sta tistical enhancement of the spontaneous emission rates, sensitive to t he final-state occupation. The description is specialized to treat ato ms with a J = 1 --> J' = 1 transition in a one-dimensional sigma(+)-si gma(-) VSCPT configuration. The TDHF equations are integrated numerica lly. It is shown that for a density at which the gas is optically dens e, the number of atoms, trapped in the dark state, is increased and it s momentum width is decreased.