Spatial instabilities in a cloud of cold atoms

TL;DR

This paper investigates the spatial characteristics of instabilities in dense cold atomic clouds, revealing that their dynamics are localized and cannot be described by traditional eigenmode analysis, highlighting complex space-time interactions.

Contribution

It provides the first experimental analysis of the spatial nature of stochastic instabilities in cold atomic clouds, demonstrating the non-separable space-time dynamics.

Findings

Dynamics are localized in space

Spectral and spatial analyses fail to identify eigenmodes

Space and time are not separable in the dynamics

Abstract

Dense cold atomic clouds have been shown to be similar to plasmas. Previous studies showed that such clouds exhibit instabilities induced by long-range interactions. However they did not describe the spatial properties of the dynamics. In this Letter, we study experimentally the spatial nature of stochastic instabilities and find out that the dynamics is localized. Data are analyzed both in the spectral domain and in the spatial domain (principal component analysis). Both methods fail to describe the dynamics in terms of eigenmodes, showing that space and time are not separable.