Self-organization processes and transport properties of light in cold atomic clouds
Abstract
Atomic clouds are versatile and well-isolated platforms allowing to simulate and study in laboratory other complex systems that are more elusive to measurement and manipulation, for example, astrophysical or solid state systems. Particularly interesting are phenomena that can be induced by injected light fields, such as interatomic forces leading to stress called "optical stress". The study of these phenomena, namely the propagation of these optical forces, and the reorganization of the cloud they may lead to, is the main objective of this research proposal. The project comprises two main research lines: The first line addresses the propagation of a macroscopic excitation within the cloud. Such an excitation does not simply propagate at the speed of light, as it may rely on many scattering events, each taking a finite time. Then, we investigate the effect of this macroscopic excitation on the atoms since a scattering event is no more a '1 atom+1 photon' process, as the interference of other atoms come into play. In particular, we intend to shed a new light on the Abraham-Minkowski controversy. The second part of this project focuses on the atomic motion under the effect of this optical stress. The first point is to understand how the transport properties of the light are affected by these optical forces, as the light drives the atoms. The second goal is to understand whether reorganization in presence of high densities of matter or photons may lead to some singular behaviors, such as "photon bubbles". Finally, we aspire to find regimes where self-organization process in two and three dimensions are triggered. (AU)