  We investigate the stability of quantum Markov processes with respect to
perturbations of their transition maps. In the first part, we introduce a
condition number that measures the sensitivity of fixed points of a quantum
channel to perturbations. We establish upper and lower bounds on this condition
number in terms of subdominant eigenvalues of the transition map.
  In the second part, we consider quantum Markov processes that converge to a
unique stationary state and we analyze the stability of the evolution at finite
times. In this way we obtain a linear relation between the mixing time of a
quantum Markov process and the sensitivity of its fixed point with respect to
perturbations of the transition map.
