The single-photon reflectivity in the system with two atoms in the supercavity. (a) With n₁ = 9 (near node) and n₂ = 12 (antinode). (b)n₁ = 12 (antinode) and n₂ = 15 (near node). All the other parameters are the same as those in Fig. 2. The part between the two red dashed vertical lines is the reflectivity peak. It is clear that a drop appears in the middle of that peak, i.e., in the region around Δ = 0. Due to this drop, the single peak of the reflectivity quantitatively splits into two peaks, and δ is also defined as δ = Δ − E_k.