Magneto-optical properties of a quantum dot array interacting with a far-infrared photon mode of a cylindrical cavity

We model the equilibrium properties of a two-dimensional electron gas in a square lateral superlattice of quantum dots in a GaAs heterostructure subject to an external homogeneous perpendicular magnetic field and a far-infrared circular cylindrical photon cavity with one quantized mode, the TE011 mode. In a truncated linear basis constructed by a tensor product of the single-electron states of the noninteracting system and the eigenstates of the photon number operator, a local spin density approximation of density functional theory is used to compute the electron-photon states of the two-dimensional electron gas in the cavity. The common spatial symmetry of the vector fields for the external magnetic field and the cavity photon field in the long wavelength approximation enhances higher order magnetic single- and multi-photon processes for both the para- and the diamagnetic electron-photon interactions. The electron-photon coupling introduces explicit photon replicas into the bandstructure and all subbands gain a photon content, constant for each subband, that can deviate from an integer value as the coupling is increased or the photon energy is varied. The subbands show a complex Rabi anticrossing behavior when the photon energy and the coupling bring subbands into resonances. The complicated energy subband structure leads to photon density variations in reciprocal space when resonances occur in the spectrum. The electron-photon coupling polarizes the charge density and tends to reduce the Coulomb exchange effects as the coupling strength increases.