  Electronic transport through nanostructures can be suppressed by coherent
population trapping, in which quantum coherence leads to a dark state that
decouples from the drain electrode. Finite transport, then, relies on
decoherence of the dark state. An alternative scenario for reduced transport is
weak coupling of a state, referred to as a blocking state, to the drain. This
raises the question of whether and how these two scenarios can be distinguished
in the transport features. For the example of electron transport through a
carbon nanotube, we identify regimes, in which this distinction is possible by
analyzing the full counting statistics in terms of Lee-Yang zeros and factorial
cumulants.
