We consider a T-shaped, one-dimensional quantum waveguide containing an attractive or repulsive impurity in the lateral stub, and study how the resonance poles move in the complex k-plane when the strength or the position of the defect changes. Similarities and differences with respect to...

We have studied the behavior of the S–matrix poles near threshold for quantum waveguides coupled to a cavity with a defect. We emphasize the occurrence of both dominant and shadow poles on the various sheets of the energy Riemann surface, and show that the changes of the total conductivity...

We consider T–shaped, two–dimensional quantum waveguides containing attractive or repulsive impurities with a smooth, realistic shape, and study how the resonance behavior of the total conductance depends upon the strength of the defect potential and the geometry of the device. The resonance...

We report the inclusion of temperature effects on the Mahan-Nozières-De Dominicis framework to study both many-body and temperature effects in photoluminescence spectra of doped semiconductors. The electronic part of the correlation function characterizes the photoluminescence spectra. We have...

We present investigations of the electronic and magnetic structure of the Rare Earth valence states. In particular, we have examined ultra thin films (≤ 10 ML) of the rare earth metals gadolinium and neodymium epitaxially grown on tungsten (110). Various experiments on dichroism in angular...

A model study of the characteristic signatures of carrier-correlation effects on the excitonic differential absorption spectra in semiconductors is presented. Using an effectively one-dimensional tight-binding system Coulomb-induced carrier-correlations up to third-order in the optical field are...