On the Atom-exciton Interaction

Adrian Kantian, Andrew J. Daley, Päivi Törmä +1 more

We discuss atomic lattice excitons (ALEs), bound particle–hole pairs formed by fermionic atoms in two bands of an optical lattice. Such a system provides a clean set-up, with tunable masses and interactions, to study fundamental properties of excitons including exciton condensation. We also find that for a large effective mass ratio between particles and holes, effective long-range interactions can mediate the formation of an exciton crystal, for which superfluidity is suppressed. Using a combination of mean-field treatments, bosonized theory based on a Born–Oppenheimer approximation, and one-dimensional (1D) numerical computation, we discuss the properties of ALEs under varying conditions, and discuss in particular their preparation and measurement.

J. J. Hopfield

Yu-xi Liu, Chang-qi Cao, Hui W. Cao

The effect of the exciton-exciton interaction on the resonance fluorescence of quantum-well excitons is studied. At relative low exciton density, the resonance fluorescence exists only when the exciton-exciton interaction is not negligible. The fluorescence spectrum changes from one peak to two peaks when the pump light intensity is increased beyond a critical value. The fluorescence light is antibunching when the mean exciton number in the quantum well is more than 0.5. The difference between exciton resonance fluorescence and two-level atom resonance fluorescence is presented.

Christo I. Ivanov, H. Barentzen, Marvin D. Girardeau

Zoubi, H.

Dark and bright excitons are shown to appear naturally in a linear atomic super-lattice with two atoms per unit cell.In bringing the super-lattice into a strong coupling regime with a onedimensional nanophotonic waveguide, bright excitons and photons are coherently mixed to form polaritons. Treating excitons as bosons implies a mechanism that forbids two excitations from being at the same atomic state, which is included here through a bosonization procedure with kinematic interactions.Interestingly these interactions couple dark and bright excitons, and which we exploit as a new tool for exciting dark states in a controllable way.We suggest a pump-probe experiment where two polaritons scatter into two dark excitons that found to be correlated and are represented as dark bogolon-excitons.The results can be adapted for any super-lattice of active materials, e.g., of organic molecules.

Claus F. Klingshirn