Phase-coherence time saturation in mesoscopic systems: wave function   collapse
  A finite phase-coherence time $\tau_{\phi}^{meas}$ emerges from iterative measurement onto a quantum system. For a rapid sequence, the phase-coherence time is found explicitly. For the stationary charge conduction problem, it is bounded. At all order, in the time-interval of measurements, we propose a general expression for $\tau_{\phi}^{meas}$. 
J. C. Flores