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 $\delta \sigma$ at $T=0\mathrm{}$. For 1D systems the latter is found to be $\delta \sigma /\sigma \propto 1/\sqrt{N}$, where $N$ is the number of conducting channels.

• Received 8 October 1997

DOI:https://doi.org/10.1103/PhysRevLett.81.1074