Intrinsic decoherence in mesoscopic systems

We present measurements of the phase coherence time tau(phi) in six quasi-1D Au wires and clearly show that tau(phi) is temperature independent at low temperatures. We suggest that zero-point fluctuations of the phase coherent electrons are responsible for the observed saturation of tau(phi). We introduce a new functional form for the temperature dependence and present the results of a calculation for the saturation value of tau(phi). This explains the observed temperature dependence of our samples as well as many 1D and 2D systems reported to date.