Renormalization-group approach to the problem of conduction through a nanostructure

We present a numerical renormalization-group computation of the zero-temperature conductance of a nanostructure coupled to two metallic leads. In our model, the leads are represented by conduction bands of noninteracting electrons and a single level containing up to two interacting electrons represents the nanostructure. The nanostructure energy is controlled by a gate potential V-g. We show that the frequency dependence of the linear conductance through the nanostructure can be computed from the impurity spectral density of the spin-degenerate Anderson model. We compute the latter numerically and determine (i) the frequency-dependent conductance for an illustrative value of V-g, and (ii) the zero-frequency conductance as a function of V-g.