Decoherence and the Thouless Crossover in One-Dimensional Conductors

The temperature and magnetic-field dependences of the resistance of one-dimensional (1D) conductors have been studied in the vicinity of the Thouless crossover. We find that the temperature dependence of the phase coherence time τ_φ does not saturate, and the quasiparticle states remain well defined on the weak localization side of the crossover. This fact, as well as observation of the Thouless crossover in 1D samples, argues against the idea of intrinsic decoherence by zero-point fluctuations of the electrons [Mohanty et al., Phys. Rev. Lett. 78, 3366 (1997)]. We believe that frequently observed saturation of τ_φ(T) is caused by the external microwave noise.