Relevance of many-body interactions for correlated electrons in the strong-coupling limit

TL;DR

This paper investigates the significance of many-body interactions in disordered electron systems, revealing that higher-order interactions are generated and crucial at strong-coupling fixed points, challenging existing models.

Contribution

It demonstrates that three-body and higher interactions are generated in perturbation theory and are essential for understanding strong-coupling effects in disordered electrons.

Findings

Higher-order interactions are generated in perturbation theory.

These interactions are important at strong-coupling fixed points.

Standard models are incomplete for strong-coupling analysis.

Abstract

Many-body interactions in effective field theories for disordered interacting electrons are considered. It is shown that three-body and higher interaction terms are generated in perturbation theory, and some of the physical consequences of these interactions are discussed. It is shown in particular that they will in general be important for any effects governed by strong-coupling fixed points. This implies that the usual generalized nonlinear sigma-model for disordered electron systems is incomplete, and not suitable for studying strong-coupling effects.