Fig. 1. Many-body decay is determined by the distance between atoms and the array’s dimensionality.

Inverted atoms placed at the same location (d → 0) interact with each other and decay collectively via the emission of a burst of light, with a peak at time $t_{\max }$. This is the hallmark of Dicke superradiance. In contrast, atoms that are far separated (d → ∞) emit as single entities, in the form of an exponentially decaying pulse. For extended finite arrays, there is a critical distance at which the crossover between a superradiant burst and monotonically decreasing emission occurs.