Dark bogolon-excitons in a linear atomic super-lattice

Atomic lattice excitons: from condensates to crystals

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 setup to study fundamental properties of excitons, ranging from condensation to exciton crystals (which appear for a large effective mass ratio between particles and holes). Using both mean-field treatments and 1D numerical computation...

Brightening the dark excitons

Optical properties of semiconductors are dominated by excitons, which are electron –hole pairs bound by Coulomb interactions. Excitons can be bright or dark depending on the spin orientation of the individual carriers. In a bright exciton the electron and the hole have antiparallel spins and can recombine easily through the emission of a photon. In a dark exciton the spins are parallel and the ...

Gravitational Excitons as Dark Matter ∗

In earlier work it was pointed out that for warped product spacetimes the conformal (geometrical moduli) excitations of the internal compactified factor spaces should be observable as massive scalar fields in the external spacetime. Here we show that these scalar fields (gravitational excitons) describe weakly interacting particles and can be considered as dark matter component. Masses of the g...

Lattice rearrangement induced by excitons in cryocrystals

The self-trapping of excitons in atomic cryocrystals induces a variety of atomic processes including mass diffusion, and defect formation [1–4]. The basis for the physics of these phenomena is a concentration of the electronic excitation energy within a volume about that of a unit cell. Release of the energy can induce different kinds of lattice rearrangement. The above phenomena have been the ...

Increasing the Atomic Density in a Near Resonant Dark Optical Lattice