  We prove a maximal velocity bound for the dynamics of Markovian open quantum
systems. The dynamics are described by one-parameter semi-groups of quantum
channels satisfying the von Neumann-Lindblad equation. Our result says that
dynamically evolving states are contained inside a suitable light cone up to
polynomial errors. We also give a bound on the slope of the light cone, i.e.,
the maximal propagation speed. The result implies an upper bound on the speed
of propagation of local perturbations of stationary states in open quantum
systems.
