Intuitively, the generalized Tavis-Cummings (GTC) Hamiltonian is to the generalized dipole gauge Hamiltonian as the Jaynes-Cummings Hamiltonian is to the traditional dipole gauge Hamiltonian. In this manner, there are a series of approximations from Eq. 101 to get the GTC Hamiltonian. Namely, we first truncate each molecule to the two-level approximation and remove the permanent dipole, such that the dipole operator for a given molecule can be written as μJ = µ eg J σx , where µ eg J is the transition dipole moment between the ground and excited state for molecule J. Then, the dipole selfenergy terms (last line of Eq. 101) are neglected entirely. Finally, the rotating wave approximation is performed such that the interaction terms go as