Observation of single-photon superradiance and the cooperative Lamb shift in an extended sample of cold atoms

TL;DR

This paper presents direct time-resolved observations of single-photon superradiance and the cooperative Lamb shift in cold rubidium atoms, revealing their dependence on atom number and sample shape, highlighting collective quantum effects.

Contribution

It provides the first direct measurements of superradiance and Lamb shift in an extended cold atom sample, demonstrating their scaling with atom number and shape dependence.

Findings

Decay rate scales linearly with atom number

Lamb shift depends on sample shape

Superradiance observed in extended cold atom sample

Abstract

We report direct, time-resolved observations of single-photon superradiance in a highly extended, elliptical sample of cold 87Rb atoms. The observed rapid decay rate is accompanied by its counterpart, the cooperative Lamb shift. The rate of the strongly directional decay, and the associated shift, scale linearly with the number of atoms and show a strong dependence on the sample shape, demonstrating the collective nature of the observed quantities.