# Decay dynamics in the coupled-dipole model

## TL;DR

This paper investigates the decay dynamics of cooperative light scattering in dilute cold atomic clouds using a scalar coupled-dipole model, revealing scaling laws and coherence effects related to super- and subradiance.

## Contribution

It introduces systematic numerical studies with an exclusion volume to match experimental regimes and explores phase-shifted laser fields to highlight coherence effects.

## Key findings

- Scaling laws for super- and subradiance are established.
- Enhanced subradiance occurs with phase-shifted laser fields.
- Numerical limits and density effects are analyzed.

## Abstract

Cooperative scattering in cold atoms has gained renewed interest, in particular in the context of single-photon superradiance, with the recent experimental observation of super-and subradiance in dilute atomic clouds. Numerical simulations to support experimental signatures of cooperative scattering are often limited by the number of dipoles which can be treated, well below the number of atoms in the experiments. In this paper, we provide systematic numerical studies aimed at matching the regime of dilute atomic clouds. We use a scalar coupled-dipole model in the low excitation limit and an exclusion volume to avoid density-related effects. Scaling laws for super-and subradiance are obtained and the limits of numerical studies are pointed out. We also illustrate the cooperative nature of light scattering by considering an incident laser field, where half of the beam has a $\pi$ phase shift. The enhanced subradiance obtained under such condition provides an additional signature of the role of coherence in the detected signal.