Ultralong-Range Interactions and Blockade of Excitation in a Cold Rydberg Gas

摘要

We review our recent experiments on interaction-induced effects in a gas of Rydberg atoms excited from a laser-cooled rubidium cloud. The van-der-Waals interaction between a pair of Rydberg atoms separated as far as 100,000 Bohr radii features two important effects: Spectral broadening of the resonance lines and suppression of excitation with increasing Rydberg density. The line broadenings are interpreted in terms of level shifts of Rydberg pairs due to their interaction. The density-dependent suppression of excitation marks the onset of an interaction-induced local blockade.