We report measurements of the inelastic neutron scattering spectrum for the anisotropic intermediate valence system Yb2Rh3Ga9. Calculations for the Anderson impurity model with crystal field terms within an approach based on the non-crossing approximation have been performed for the inelastic neutron scattering spectrum as well as other thermodynamic quantities. These results corroborate the im...

The features of InAs quantum dots obtained on GaAs(001) single-crystal substrates by ion-beam sputtering were investigated. It has been shown that in the range of ion energies of 150 to 200 eV at a temperature of 500 °C and a beam current of 120 µA InAs quantum dots with average dimensions below 15 nm and a surface density of 1011 cm-2 are formed. The technique of controlled doping of InAs/GaAs...

– A generalized Anderson model for a magnetic impurity in an interacting onedimensional electron gas is studied via a mapping onto a classical Coulomb gas. For weak potential scattering, the local-moment parameter regime expands as repulsive bulk interactions become stronger, but the Kondo scale for the quenching of the impurity moment varies nonmonotonically. There also exist two regimes domin...

We study the interaction-induced localization – the so-called self-trapping – of a neutral impurity atom immersed in a homogeneous Bose-Einstein condensate (BEC). Based on a Hartree description of the BEC we show that – unlike repulsive impurities – attractive impurities have a singular ground state in 3d and shrink to a point-like state in 2d as the coupling approaches a critical value β⋆. Mor...

– We study the effect of mesoscopic fluctuations on a magnetic impurity coupled to a spatially confined electron gas with a temperature in the mesoscopic range (i.e. between the mean level spacing ∆ and the Thouless energy ETh). Comparing “poor-man’s scaling” with exact Quantum Monte Carlo, we find that for temperatures larger than the Kondo temperature, many aspects of the fluctuations can be ...

Models of quantum computing rely on transformations of the states of a quantum memory. We study mathematical aspects of a model proposed by Wu in which the memory state is changed via the scattering of incoming particles. This operation causes the memory content to deviate from a pure state, i.e. induces impurity. For nonrelativistic particles scattered from a two-state memory and sufficiently ...

We study the spectral shape and the magnetic field induced polarization of hot-electron photoluminescence from the diluted magnetic semiconductor Ga,Mn As. It is demonstrated that the holes occupy predominantly the impurity band and not the valence band as required for the Rudermann-Kittel-Kasuya-Yosida-type exchange interaction. We show that the ground state of the impurity band is split by un...

Effects of the superconducting pair potential on the impurity scattering processes in metallic carbon nanotubes are studied theoretically. The backward scattering of electrons vanishes in the normal state. In the presence of the superconducting pair correlations, the backward scatterings of electronand hole-like quasiparticles vanish, too. The impurity gives rise to backward scatterings of hole...