Collective Radiance and Dynamics in Multi-Level Atom Nano-Rings

Abstract

The collective spontaneous emission of an ensemble of atoms trapped in a ring configuration is studied when the interparticle distance is smaller than the transition wavelength. Here, interference effects between scattered fields can lead to the enhancement or suppression of the collective atomic decay rates from an excited state, a phenomenon known as superradiance or subradiance, respectively. In this work we study these phenomena in isotropic atoms with three possible degenerate transitions from the ground state to excited states, when a single excitation is present in the system. In addition, we study the excitation transport in the ring and show that subradiant states can be useful to enhance the efficiency in the process, compared to non-interacting atoms