Ref. 424 implemented a QM/MM excited state molecular dynamics approach to simulate a large ensemble of molecules coupled to a cavity photon mode. Specifically, they implemented the mean-field Ehrenfest approach, where the electronic and photonic degrees of freedom are treated quantum mechanically while the nuclear degrees of freedom are evolved classically. They used the Tavis-Cummings Hamiltonian (see Eq. 12), obtaining the energies and transition dipole matrix element for each individual molecule on a separate CPU/GPU in parallel, thus allowing them to perform large-scale excited state molecular dynamics inside an optical cavity.