Förster dynamics within the Stark manifold

The resonant energy exchange among ultracold Rydberg atoms has been used as an analog to shed light on the dynamics in quantum systems. However, most studies of the dipole-dipole interaction have explored systems with few initial and final states. We have measured the time dependence of the dipole-dipole-mediated redistribution of population among manifold states for atoms initially excited near the center of the Stark manifold, where the states form a nearly harmonic ladder. Energy exchange occurs rapidly but is limited due to the increasing anharmonicity of more distant manifold energy levels. We compare our experimental results to a computational model which includes about 40 manifold levels.