We describe the fundamental equations for description of electron-photon interactions in insulating nanostructures. Since the theory for the nanostructures are based on the theory for the bulk crystals, we shall describe elements of the theory for the bulk crystals [1]-[3] in the first three subsections. It is important in discussions on optical phenomena that both the envelope function and the...

We report observation of Wannier-Stark ladders with ultracold sodium atoms in an accelerating one-dimensional standing wave of light. Atoms are trapped in a far-detuned standing wave that is accelerated for a controlled duration. A small oscillatory component is added to the acceleration, and the fraction of trapped atoms is measured as a function of the oscillation frequency. Resonances are ob...

A recently proposed approach for performing electronic-structure calculations on crystalline insulators in terms of localized orthogonal orbitals is applied to the oxides of lithium and sodium, Li2O and Na2O. Cohesive energies, lattice constants and bulk moduli of the aforementioned systems are determined at the Hartree-Fock level, and the corresponding values are shown to be in excellent agree...

Classical MD data on the dynamic charge-charge structure factor Szz(k, ω) of semi-quantal hydrogen plasmas modelled in [1] are revisited using the sum rules and other exact relations to reconstruct the system loss function, and the method of effective potentials to estimate its static characteristics. Introduction Classical molecular dynamics (MD) simulations of model hydrogen plasmas were carr...

The wave equation for two electrons in an external Coulomb field (heliumlike atoms) has been shown to be a problem in a three-dimensional half-space. The wave-equation becomes quasi-separable in inertial coordinates. This allows to work out the electron motion in the frame of principal inertia axes. We find that non-adiabatic coupling terms constitute a fictitious force and lead to a deformatio...

In this paper we present calculations on the electronic band structure of a two-dimensional lateral superlattice subject to a perpendicular magnetic field by employing a projection operator technique based on the ray-group of magnetotranslation operators. We construct a new basis of appropriately symmetrized Bloch-like wavefunctions as linear combination of well-localized magnetic-Wannier funct...

We study the behavior of several physical properties of the Haldane model as the system undergoes its transition from the normal-insulator to the Chern-insulator phase. We find that the density matrix has exponential decay in both insulating phases, while having a power-law decay, more characteristic of a metallic system, precisely at the phase boundary. The total spread of the maximally locali...

Spatially direct and indirect Stark ladder optical transitions and their electric field induced evolution have been investigated in a GaAs/AlAs (LZ = 6.4 nm/LB = 0.9 nm) superlattice by low temperature photocurrent spectroscopy. When the ground and first excited electron Stark ladder states resonate between the nearest neighbor wells, it is found that oscillator strengths of the direct (n = 0) ...

A theory describing vibronic coupling in direct band gap, one-dimensional semiconductors is developed to account for the photophysical properties of isolated, defect-free conjugated polymers. A Holstein-like Hamiltonian represented in a multi-particle basis set is used to evaluate absorption and emission due to Wannier-Mott excitons. The photophysical properties of such quantum wires are shown ...