Abstract

The interaction of photons with ultra cold trapped atomic gases is a subject of current interest. Here we investigate the dynamics of identical atoms situated in a micro trap which interact via the induced dipole-dipole interaction. In particular we study the case of two atoms in which one atom is initially excited and the other atom is in the electronic ground state. While previous studies have focused on the spectrum of spontaneous emission from such a system, we here concetrate on the consequences for the final distribution of the atoms over the trap states. Also, in contrast to previous studies, which are mostly based on a two-level atom approximation, we here take into account the full vector character of the induced dipole moments and the tensor charcter of the dipole-dipole interaction. Our studies are motivated by the fact that neither do the matrix elements of the dipole-dipole interaction potential exist in any possible basis of single-body states, nor is the exactly calculated scattering length finite. The latter implies in particular the break down of the so-called T-matrix approximation whcih is frequently used in many-body theory.

© 1996 Optical Society of America