V. RESULTS AND DISCUSSIONS 1. Linear Response Signal Fig. presents the time-dependent linear response signal, R (t) and the linear absorption spectra, R (ω), simulated using the PLDM approach. In this figure, we do not account for any type of disorder, and we keep √ N ℏg c a constant as we change N . Fig. and Fig. present the linear response signal and the linear absorption spectra for N = 5 molecules coupled to the cavity, respectively. For the R (ω) data, we shift the axis with respect to ℏω 0 = ε, so the spectra are centered around zero instead of ε. A clear observation of the linear response signal indicates the presence of two types of oscillations that arise due to the two polaritonic transitions, |G 0 ⟩ → |-⟩ and |G 0 ⟩ → |+⟩, as observed in the two peaks in linear spectra at ℏω -ε ≈ -100 meV and ℏω -ε ≈ 100 meV, respectively. Due to symmetry, there is no optical transition from |G 0 ⟩ to the dark state manifold {|D k ⟩}.