Light–matter systems bring many emitters (e.g., atoms) into a shared optical mode inside a cavity. This mode forms a stable pattern of light between mirrors placed very close together, creating conditions that allow the atoms to act collectively in ways that isolated atoms cannot. One of the most striking examples is superradiance, a coordinated quantum effect in which a large group of atoms emits light in perfect synchrony, producing a much stronger burst than they would individually.
Many theoretical studies assume that the interaction between light and matter is the dominant force in these systems. Under this assumption, researchers often treat the entire group of atoms as a unified “giant dipole,” evenly linked to the cavity field. This field creates interactions across the whole ensemble as if every atom were connected to all others.
“Photons act as mediators that couple each emitter to all others inside the cavity,” says Dr. João Pedro Mendonça, the first author of the article, who completed his PhD at the Faculty of Physics of the University of Warsaw and is now working as a researcher at the Centre for New Technologies at the University of Warsaw.
In actual materials, however, atoms that sit close together also influence one another through short-range dipole–dipole interactions that are frequently ignored. The researchers examined what happens when these intrinsic atom-atom effects are included. Their findings show that these local interactions can either weaken or strengthen the longer-range processes driven by photons, directly affecting whether superradiance occurs. Understanding this relationship is crucial for interpreting experiments in conditions where light and matter strongly affect one another.
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