Dynamic wavepackets in coherently controlled rubidium dimers

The success in cooling and trapping atomic gases to the point of quantum degeneracy has prompted a quest to create ultracold molecular gases. Atomic techniques can not be applied to molecular gases due to their richer internal structure. Effort has been applied to converting ultracold atoms to ultracold molecules. This should be done without the use of spontaneous decay to attain the coldest possible temperatures. A scheme has been suggested, in the works of Koch et al. (2006) and Mur-Petit et al. (2007) that mandates the excitation of preformed loosely bound atom pairs which then oscillate coherently and may be deexcited back to less vibrationally excited states. For this to work, knowledge of the behaviour of the excited wavepacket in a realistic experimental setting is essential. In this paper, the authors report on the calculation of a time-dependent wavefunction starting from a measured initial state under the influence of a measured excitation pulse.