  We derive a non-Markovian theory for waiting time distributions of
consecutive single electron transfer events. The presented microscopic Pauli
rate equation formalism couples the open electrodes to the many-body system,
allowing to take finite bias and temperature into consideration. Numerical
results reveal transient oscillations of distinct system frequencies due to
memory in the waiting time distributions. Memory effects can be approximated by
an expansion in non-Markovian corrections. This method is employed to calculate
memory landscapes displaying preservation of memory over multiple consecutive
electron transfers.
