Discrete solitons in an array of quantum dots

We develop a theory for the interaction of classical light fields within a chain of coupled quantum dots (QDs), in the strong-coupling regime, taking into account the local-field effects. The QD chain is modeled by a one-dimensional periodic array of two-level quantum particles with tunnel coupling between adjacent ones. The local-field effect is taken into regard as QD depolarization in the Hartree-Fock-Bogoliubov approximation. The dynamics of the chain is described by a system of two discrete nonlinear Schrodinger (DNLS) equations for local amplitudes of the probabilities of the ground and first excited states. The two equations are coupled by cross-phase-modulation cubic terms, produced by the local-field action, and by linear terms also. In comparison to previously studied DNLS systems, an essentially new feature is a phase shift between the intersite-hopping constants in the two equations. By means of numerical solutions, we demonstrate that, in this QD chain, Rabi oscillations (RO) self-trap into stable bright Rabi solitons or Rabi breathers. The mobility of the solitons is considered as well. The related behavior of the observable quantities, such as energy, inversion, and electric-current density, is given a physical interpretation. The results apply to a realistic region of physical parameters