where we introduced a coupling parameter for this more complicated system, λ k,n = ℏ ϵ0V êk,n . While this is rigorous, its computational cost can quickly become enormous. The following simple basis size analysis can demonstrate this. For j molecules with l electronic states and m modes with n Fock states, the basis size scales as l j n m . Due to this unfavorable scaling, the generalized Tavis-Cummings Hamiltonian is a useful approximation to simulate these systems.