Fig. 2

Breakdown of the Rabi model observed through the system dynamics. a Contour plot of the TLS population versus time and coupling rate. The dashed line marks the value g/ω_c ≈ 0.6 chosen for the rest of the simulations. Above this value, the single-mode Rabi model differs drastically from the multi-mode model. Insets on the right show a zoom view around a revival peak. b Population of an initially excited TLS versus time for the single-mode (blue, dashed) and multi-mode (red, solid) cases, for a coupling rate of g/ω_c = 0.6. c Amplitude of the electric field inside the cavity (square root plotted for clarity) as a function of space and time, for g/ω_c = 0.6. The inset focus on the precise moment when the field is perfectly absorbed by the emitter, giving rise to the revival peaks in the population of the TLS. Computed using the technique of MPS including 50 cavity modes