Quantum Decoherence in Disordered Mesoscopic Systems

Abstract

We point out that the low temperature saturation of the electron phase decoherence time in a disordered conductor can be explained within the existing theory of weak localization provided the effect of quantum (high frequency) fluctuations is taken into account. Making use of the fluctuation-dissipation theorem we evaluate the quantum decoherence time, the crossover temperature below which thermal effects become unimportant, and the weak localization correction $\ensuremath{\delta}\ensuremath{\sigma}$ at $T\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0$. For 1D systems the latter is found to be $\ensuremath{\delta}\ensuremath{\sigma}/\ensuremath{\sigma}\ensuremath{\propto}1/\sqrt{N}$, where $N$ is the number of conducting channels.