Decoherence of interacting electrons in disordered conductors: on the relation between influence functional and diagrammatic approaches

Abstract

We establish a connection between the influence functional approach of Golubev and Zaikin (GZ) and Keldysh diagrammatic perturbation theory for calculating the decoherence time of interacting electrons in disordered metals; we show how the standard diagrams for the Cooperon self energy can be recovered from GZ's influence functional $e^{- (i S_R + S_I)}$. This allows us to shed light on GZ's claim that $S_R$ is irrelevant for decoherence: $S_R$ generates as many important self energy diagrams as $S_I$; GZ's neglect of $S_R$ is permissible only at high temperatures ($T > \hbar / τ_{el}$).

6 pages LaTeX, 2 figures, for conference proceedings: "Quantum Transport and Quantum Coherence" -- Localisation 2002 Sophia University, Tokyo, August 16-19, 2002, to be published in a supplement of the Journal of Physical Society of Japan