  It is shown in this paper that the quantum master equation can be mapped to a
modified continuous time random walk (CTRW) if the relaxation term is composed
of transitions over a set of states. When the Hamiltonian is time-independent
and transitions are between its eigenlevels, such a modified CTRW reduces to
the Markovian walk equivalent to the Pauli master equation. On the other hand,
the memory in such a modified CTRW is composed of a temporal factor and the
probability determined by the Liouville flow when the relaxation term is
reduced as a special dephasing term.
