Title: Rydberg Wavepacket Evolution in a Frozen Gas of Dipole-Dipole Coupled Atoms

Tao Zhou, Sha Li, and R.R. Jones

University of Virginia, Charlottesville, VA 22904, USA

Abstract:

We have studied the evolution of Rydberg wavepackets in the presence of interatomic dipole-dipole interactions in a frozen Rb gas. Rb atoms in a MOT are first laser-excited to ns Rydberg eigenstates. A picosecond THz pulse further excites them into coherent superposition states involving the initial-level and neighboring np-states. A second, identical, time-delayed THz pulse probes the wavepacket dynamics. As the wavepackets evolve they are influenced by dipole-dipole interactions, predominantly pairwise excitation-exchange processes of the form sp <-> ps. The coherent electronic evolution of the ensemble dephases due to the variation in dipole-dipole coupling strength between atom pairs in the MOT. The experimental results are in good agreement with numerical calculations that simulate the interactions between nearest neighbors in a frozen gas.

Status: Published Physical Review A 89, 063413 (2014) .