Rabi oscillations between ground and Rydberg states and van der Waals blockade in a mesoscopic frozen Rydberg gas

TL;DR

This paper reports on the observation of Rabi oscillations between ground and Rydberg states in a mesoscopic ultracold atom ensemble, analyzing decoherence sources and demonstrating van der Waals blockade, advancing the study of many-body quantum phenomena.

Contribution

It provides a detailed experimental analysis of Rabi oscillations and van der Waals blockade in a mesoscopic Rydberg gas, highlighting new insights into coherent many-body dynamics.

Findings

Observation of synchronous Rabi oscillations in a mesoscopic Rydberg ensemble

Analysis of decoherence effects such as spatial fluctuations and state redistribution

Demonstration of van der Waals blockade in a mesoscopic atomic sample

Abstract

We present a detailed analysis of our recent observation of synchronous Rabi oscillations between the electronic ground state and Rydberg states in a mesoscopic ensemble containing roughly 100 ultracold atoms [M. Reetz-Lamour \textit{et al.}, submitted, arXiv:0711.4321]. The mesoscopic cloud is selected out of a sample of laser-cooled Rb atoms by optical pumping. The atoms are coupled to a Rydberg state with principal quantum number around 30 by a two-photon scheme employing flat-top laser beams. The influence of residual spatial intensity fluctuations as well as sources of decoherence such as redistribution to other states, radiative lifetime, and laser bandwidth are analysed. The results open up new possibilities for the investigation of coherent many-body phenomena in dipolar Rydberg gases. As an example we demonstrate the van der Waals blockade, a variant of the dipole blockade, for a mesoscopic atom sample.