Harvard Condensed Matter Theory Seminars

Abstract

Jan von Delft, University of Munich

Decoherence in Disordered Conductors by Interactions and Magnetic Impurities

In this talk, we revisit the problem of decoherence in weak localization. The basic challenge addressed in our work is to calculate the decoherence of electrons interacting with a quantum-mechanical environment, while taking proper account of the Pauli principle. We show how this may be done using an influence-functional approach, and verify that the result is consistent with much more laborious diagrammatic calculations. We demonstrate how the Pauli principle serves to suppress the decohering effects of quantum fluctuations of the environment, and essentially confirm the classic result of Altshuler, Aronov and Khmelnitskii for the energy-averaged decoherence rate, which vanishes at zero temperature. Going beyond that, we employ our method to calculate explicitly the leading quantum corrections to the classical decoherence rates, and to provide a detailed analysis of the energy-dependence of the decoherence rate. Time permitting, we shall also briefly discuss decoherence in the presence of magnetic impurities.