Interaction and quantum decoherence

We discuss a fundamental effect of the interaction-induced decoherence of t he electron wave function in disordered metals. In the first part of the pa per we consider a simple model of a quantum particle interacting with a bat h of harmonic oscillators and analyze the physical origin of the effect. Th is exactly solvable model also allows to understand why the arguments again st 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 diso rdered metals. (C) 1998 Elsevier Science B.V. All rights reserved.