Intrinsic Decoherence in Mesoscopic Systems

TL;DR

This paper demonstrates that environmental decoherence causes the saturation of weak localization effects at zero temperature in mesoscopic systems, explaining finite phase-breaking lifetimes observed experimentally.

Contribution

It introduces a model where voltage fluctuations cause intrinsic decoherence, providing a new perspective on phase coherence loss at zero temperature in disordered metals.

Findings

Decoherence limits interference at T=0 in disordered metals.

Voltage fluctuations lead to phase-breaking and saturation of quantum corrections.

Model aligns with experimental observations of finite phase-breaking lifetimes.

Abstract

We point out that even at the absolute zero of temperature environmental decoherence limits the destructive interference between time-reversed paths for an electron in a disordered metal, and thus causes the leading (`weak localization') quantum correction to the conductivity to saturate at T=0. Our calculation, which is intended to be illustrative rather than complete, uses a model in which an electron interacts with the fluctuations of the mean voltage in the sample. The average of the fluctuations produces the steady damping well known in Brownian motion, introduces a direction of time, ensures that arbitrarily long time-reversed electron paths lose phase coherence, and is consistent with the experimental observation of a finite low temperature phase-breaking lifetime.