Optical depth dictates universal bounds on many-body decay in atomic ensembles
The paper establishes a universal scaling law for many-body decay in atomic ensembles, showing that maximum emission rate (R⋆) scales as R⋆ ∼ Γ0 N × OD. This links single-particle to superradiant regimes. It proves this bound holds generally by relating the optical depth (OD) to the atom number (N), confirming its fundamental role in many-body light-matter coupling.