  In the low-dimensional disordered systems the dephasing time and the
inelastic scattering (out-scattering) time are in general different. We show
that in the case of the two-dimensional chiral metal which is formed at the
surface of a layered three dimensional system, which is exhibiting the integer
quantum Hall effect these two quantities are essentially the same and their
temperature-dependence is T^(-3/2). In particular we show that the results
obtained using the diagramatic technique and the phase uncertainty approach
introduced by A. Stern et al. (Phys. Rev. A 41, 3436 (1990)) for the
out-scattering and the dephasing time respectively, coincide. We furthermore
consider these quantities in the case of the three-dimensional chiral metal,
where similar conclusions are reached.
