EFFECT OF INTERACTIONS ON THE ADMITTANCE OF BALLISTIC WIRES

A self-consistent theory of the admittance of a perfect ballistic, loc ally charge neutral wire is proposed. Compared to a non-interacting th eory, screening effects drastically change the frequency behavior of t he conductance. In the single-channel case the frequency dependence of the admittance is monotonic, while for two or more channels collectiv e interchannel excitations lead to resonant structures in the admittan ce. The imaginary part of the admittance is typically positive, but ca n become negative near resonances.