Intuitively, this is because the peak of J eff (ω) should match the quantum transition frequency ω 0 to maximally enhance the |ν L → |ν L transition. Since the non-Markovian spectral density is blue-shifted compared to the Markovian case, one should expect ω c < ω 0 in order to have the peak of J eff (ω) showing up at ω 0 . Thus, the resonance condition is red-shifted as ω c = ω 2 0 -R(ω 0 ). Note that this shift is purely due to the non-Markovian behavior of the photon-loss bath (which has nonzero R(ω 0 )). The numerical simulation with the non-Markovian photon-loss bath can, in principle, be performed using the recently developed time-domain Prony fitting decomposition scheme. E. Numerical Behavior of kVSC in Eq. 41