Metal to insulator crossover in mesoscopic wires

We argue that the crossover from a metal-like to an insulator-like behavior in the conductance of a mesoscopic wire, resulting from a progressive depletion of electrons, is determined by the Coulomb interaction. Two models, corresponding to strong and weak fluctuations of the background electrostatic potential that forms the wire, are discussed. In the first case, the crossover is determined by the Coulomb blockade effect in a sequence of conducting dots separated by tunnel barriers. In the opposite limit of weak potential fluctuations, formation of a quantum Wigner crystal and its pinning by residual impurities determines the crossover behavior.