Under the resonance condition (Eq. 4), kVSC is proportional to τ -1 c in the lossless regime (τ c ≫ Ω -1 R ), whereas k VSC (Eq. 2) is proportional to τ c in the lossy regime (τ c ≪ Ω -1 R ). Moreover, we proposed an interpolated rate expression between k VSC and kVSC to describe the crossover phenomenon for intermediate τ c , and predicted that the maximal enhancement will be reached at