title: Weak charge quantization as an instanton of the interacting sigma model.
abstract: Coulomb blockade in a quantum dot attached to a diffusive conductor is considered in the framework of the nonlinear sigma model. It is shown that the weak charge quantization on the dot is associated with instanton configurations of the Q field in the conductor. The instantons have a finite action and are replica nonsymmetric. It is argued that such instantons may play a role in the transition regime to the interacting insulator.
authors.affiliation: Department of Physics, Technion, Haifa 32000, Israel.
authors.forename: A
authors.initials: A
authors.lastname: Kamenev