Nonlinear Sigma Model for Disordered Media: Replica Trick for Non-Perturbative Results and Interactions

TL;DR

This paper reviews the application of the nonlinear sigma model with replicas to disordered media, focusing on non-perturbative results and a new variant for interacting electrons in disordered systems.

Contribution

It introduces a new variant of the sigma model for interacting electrons and discusses non-perturbative methods for disordered systems using the replica trick.

Findings

Oscillatory behavior of two-level correlation function

Long-tail asymptotes of mesoscopic distributions

Reduction to phase-only actions including dirty bosons

Abstract

In these lectures, given at the NATO ASI at Windsor (2001), applications of the replicas nonlinear sigma model to disordered systems are reviewed. A particular attention is given to two sets of issues. First, obtaining non-perturbative results in the replica limit is discussed, using as examples (i) an oscillatory behaviour of the two-level correlation function and (ii) long-tail asymptotes of different mesoscopic distributions. Second, a new variant of the sigma model for interacting electrons in disordered normal and superconducting systems is presented, with demonstrating how to reduce it, under certain controlled approximations, to known ``phase-only'' actions, including that of the ``dirty bosons'' model.