To calculate the dynamics of two coupled QDs (each modeled as an interband two-level system with one conduction and one valence level | c ⟩ ⟩ and | v ⟩ ⟩ , respectively) which have no electronic overlap, an expansion of the potential is performed: (i) a long-range expansion about a reference point of each QD, varying on a mesoscopic scale and neglecting the variation on the scale of the elementary cell - this yields level diagonal contributions in the Hamiltonian H cc = ∑ ∑ i > j V cc ij a c i † † a c j † † a c j a c i and H cv = ∑ ∑ i ≠ ≠ j V cv ij a c i † † a v j † † a v j a c i ; and (ii) a short-range expansion about an arbitrary lattice vector, taking into account the microscopic variation of the QD - this yields nondiagonal contributions H F = ∑ ∑ i ≠ ≠ j V F ij a c i † † a v j † † a c j a v i . On the dipole-dipole level, the level diagonal elements correspond to an electrostatic energetic shift of the system (biexcitonic shift V bs = V cv − − V cc ), while the nondiagonal elements, the so-called Förster coupling elements V F , correspond to an excitation transfer between the different QDs.