Figure 2
From: Light-matter decoupling and A2 term detection in superconducting circuits

Light-matter decoupling in presence of the A2 term (Δ ≠ 0).
Panel (a): spectral function for various values of Δ in a model with F(cq) coupling. Panel (b): value of the coefficient α in a fit to J(ω; Δ) = 2πα(Δ)ω1 for the couplings F(cq) and F(fq). In both simulations L = 10λ0 and v = 1.