Interaction and Quantum Decoherence

TL;DR

This paper investigates how electron wave functions in disordered metals lose coherence due to interactions, showing that decoherence persists at low temperatures and prevents these metals from becoming insulators at T=0.

Contribution

It provides a rigorous analysis of quantum decoherence in disordered metals and clarifies the physical origin of the effect through an exactly solvable model.

Findings

Finite quantum decoherence rate at low T.

Disordered metals do not become insulators at T=0.

Experimental results on GaAs structures support the theory.

Abstract

We discuss a fundamental effect of the interaction-induced decoherence of the electron wave function in disordered metals. In the first part of the paper we consider a simple model of a quantum particle interacting with a bath of harmonic oscillators and analyze the physical origin of the effect. This exactly solvable model also allows to understand why the arguments against the existence of the effect at low temperatures fail. The second part of the paper is devoted to a rigorous analysis of quantum decoherence in disordered metals. We also discuss the relation of our results to the recent experiments on GaAs structures. The existence of a finite quantum decoherence rate at low $T$ implies that low dimensional disordered metals with generic parameters do not become insulators even at T=0.