  Majorana zero modes (MZMs) emerging at the edges of topological
superconducting wires have been proposed as the building blocks of novel,
fault-tolerant quantum computation protocols. Coherent detection and
manipulation of such states in scalable devices are, therefore, essential in
these applications. Recent detection proposals include semiconductor quantum
dots (QDs) coupled to the end of these wires, as changes in the QD electronic
spectral density due to the MZM coupling could be detected in transport
experiments. Here, we propose that multi-QD systems can also be used to
manipulate MZMs through precise control over the QDs' parameters. The simplest
case where Majorana manipulation is possible is in a double quantum dot (DQD)
geometry. By using exact analytical methods and numerical renormalization-group
calculations, we show that the QDs' spectral functions can be used to
characterize the presence or not of MZMs "leaking" into the DQD. More
importantly, we find that these signatures respond to changes in the DQD
parameters such as gate-voltages and couplings in a consistent fashion.
Additionally, we show that different MZM-DQD coupling geometries ("symmetric" ,
"in-series" and "T-shaped" junctions) offer distinct ways in which MZMs can be
switched from dot to dot. These results highlight the interesting possibilities
that DQDs offer for all-electrical MZM control in scalable devices.
