Influence of Coulomb correlations on the quantum well intersubband absorption at low temperatures

We present a theory for the intersubband absorption including electronic ground-state correlations in a doped $\text{GaAs}/{\text{Al}}_{0.35}{\text{Ga}}_{0.65}\text{As}$ quantum well system. Focusing on the influence of the Coulomb interaction among the carriers at low temperatures, we find that the ground-state correlations lead to an increased renormalization and spectral broadening of the absorption spectrum. At $T=1\text{ }\text{K}$, its full width at half maximum is increased by up to a factor 3. The inclusion of electron-phonon scattering strongly reduces the relative impact of the electronic correlations.