The VSC experiments happen intrinsically in the collective coupling regime, where there are a large number of molecules (often > 10 10 ) coupled to the cavity modes and the light-matter coupling strength for each molecule is relatively small. Unfortunately, most theoretical works are restricted to the one molecule limit, which requires a nonphysical light-matter coupling strength or an extremely small cavity size. However, dealing with a model system with many molecules coupled to a cavity is challenging for both direct MD simulations and theoretical derivations. There have been quite a few attempts on explaining the mysterious collective effects, but more theoretical work is needed to provide a satisfactory answer.