Impact of Spontaneous Emission on the form and Dynamics of Atomic Wave Packets in an Optical Lattice

Abstract

Using the Monte Carlo wave-function method, we study the influence of spontaneous emission on dynamics of a Gaussian atomic wave packet with two internal states placed initially at a node or antinode of a standing-wave laser field. Without spontaneous emission, the wave packet at a node is known to split both in the position and momentum spaces because of the optical Stern–Gerlach effect. We show that the spontaneous-emission events suppress splitting, causing a strong broadening of the wave packet in both spaces. As for a wave packet placed initially at an antinode, spontaneous emission causes a localization of the atomic wave packet in the first potential well both in the position and momentum spaces as compared to the coherent evolution.