  We show how multi-walker quantum walks can be implemented in a quantum
quincunx created via cavity quantum electrodynamics. The implementation of a
quantum walk with a multi-walker opens up the interesting possibility to
introduce entanglement and more advanced walks. With different coin tosses and
initial states the multi-walker quantum walk shows different probability
distributions which deviate strongly from the classical random walks with
quadratic enhanced spreadings and localization effects. By introducing
decoherence, the transition from quantum walks to the classical versions is
observed. We introduce the average fidelity decay as a signature to investigate
the decoherence-induced irreversibility of quantum walks.
