Breakdown of classical electrostatics in the depolarization of quantum wires and nanotubes

In quantum wires, such as metallic nanotubes, the optical absorption of the transverse polarization is controlled by the depolarization effect which stems from the redistribution of conduction electrons around the circumference of the system. The traditional electrostatics treatment of the depolarization effect relies on approximating the system by a cylinder with some effective dielectric permittivity. We demonstrate that this simple intuitive picture does not adequately describe optical absorption near its threshold, as the depolarization effect becomes dominated by many-body correlations which strongly modify the spectral dependence of absorption.