Quantum wire hybridized with a single-level impurity

We have studied low-temperature properties of interacting electrons in a one-dimensional quantum wire (Luttinger liquid) side-hybridized with a single-level impurity. The hybridization induces a backscattering of electrons in the wire which strongly affects its low-energy properties. Using a one-loop renormalization group approach valid for a weak electron-electron interaction, we have calculated a transmission coefficient through the wire, T(epsilon), and a local density of states, nu(epsilon) at low energies epsilon. In particular, we have found that the antiresonance in T(epsilon) has a generalized Breit-Wigner shape with the effective width Gamma(epsilon) which diverges at the Fermi level.     

Boundary conditions in media with spatial dispersion

In this paper we discuss the structure of the kernel in the integral relationship between the electric field and the displacement field in a semi-infinite dielectric medium (for the exciton region of spectrum) in the presence of spatial dispersion. Using the model of coupled oscillators we derive an additional boundary condition as a function of frequency shift and damping of surface oscillators.